diff --git a/.github/workflows/windows-arm64.yml b/.github/workflows/windows-arm64.yml
index 4499e3fdc..2a8144a5b 100644
--- a/.github/workflows/windows-arm64.yml
+++ b/.github/workflows/windows-arm64.yml
@@ -29,7 +29,7 @@ permissions:
 jobs:
   windows-arm64:
     # Immutable supporting workflow revision until the new install contract lands upstream.
-    uses: storytold/craft-common-actions/.github/workflows/windows-arm64.yml@8bb4e5ab95443171104ad88113fe1ef9b0e5ce3f
+    uses: storytold/craft-common-actions/.github/workflows/windows-arm64.yml@fa5ef18780cf5e7d5d3b8de068de56cffc83cac5
     with:
       app-name: effectcraft
       app-dir: EffectCraft
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index dfa28c9f0..74d946f01 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -7,12 +7,36 @@ work apply to everyone, people and AI agents alike, and they are not negotiable.
 
 You need [Rust](https://rustup.rs/) 1.95 or newer.
 
+On Linux the desktop app plays preview sound through `cpal`, so the build needs a usable ALSA
+pkg-config package: an `alsa.pc` that pkg-config can find, naming the linkable ALSA runtime
+library (usually `libasound.so.2`). `alsa-sys` runs pkg-config at build time; it does not compile
+ALSA's headers. Without a usable package the build fails at link time with an unrelated-looking
+error; `cargo xtask ci` probes pkg-config up front and names the package:
+
+```sh
+sudo dnf install alsa-lib-devel        # Fedora
+sudo apt install libasound2-dev        # Debian / Ubuntu
+sudo pacman -S alsa-lib                # Arch
+```
+
+If you cannot install the package, point `PKG_CONFIG_PATH` at a directory holding an `alsa.pc`
+whose `Libs` line names your system's `libasound` (usually `libasound.so.2`); every CI run needs
+that variable set.
+
 ```sh
 cargo run -p effectcraft -- --demo       # the desktop app, with the demo project
 cargo test --workspace
 cargo xtask ci                           # what every commit must pass
 ```
 
+The default `dev` profile keeps debug info to line tables: builds are fast and panics/backtraces
+still name the file and line, but a debugger cannot show local variables. For an interactive
+debugger session use the `dev-full` profile, which is the same build with full debug info:
+
+```sh
+cargo run --profile dev-full -p effectcraft -- --demo
+```
+
 ## Ground rules
 
 - **Clean room.** Work from After Effects' public documentation and its observable behaviour only.
diff --git a/Cargo.lock b/Cargo.lock
index a6611ffba..a48f2d44b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1623,6 +1623,7 @@ name = "effectcraft-media"
 version = "0.18.0"
 dependencies = [
  "craft-docpath",
+ "effectcraft-color",
  "effectcraft-model",
  "effectcraft-pdf",
  "effectcraft-project",
@@ -7199,6 +7200,7 @@ name = "xtask"
 version = "0.18.0"
 dependencies = [
  "chrono",
+ "pkg-config",
  "serde_json",
  "tempfile",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index aa917fc63..dee46306d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -153,6 +153,13 @@ opt-level = 1
 # Panics and backtraces keep file and line; full debug info only made the many test binaries large.
 debug = "line-tables-only"
 
+# Same settings as `dev`, but with full debug info for interactive debugger sessions: local
+# variables, parameters and column breakpoints work. Use `--profile dev-full` when debugging;
+# everything else stays on the fast default. See CONTRIBUTING.md, "Setup".
+[profile.dev-full]
+inherits = "dev"
+debug = true
+
 # Pixel hot loops: keep debug builds interactive.
 [profile.dev.package.effectcraft-raster]
 opt-level = 3
diff --git a/README.md b/README.md
index c1f895176..12970b8ba 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@
 
 <p align="center">
   A free, open-source compositor: compositions, layers,
-  keyframes, 306 effects, layer styles, expressions, 3D cameras and lights, and a render queue, native on macOS,
+  keyframes, 308 effects, layer styles, expressions, 3D cameras and lights, and a render queue, native on macOS,
   Windows and Linux, and in the browser. Young, moving fast, and already usable.
 </p>
 
@@ -84,9 +84,10 @@ a few places where it matters to us:
   without a plugin.
 - **A project file you can read.** Projects are versioned JSON (`.ecproj`), so they diff cleanly
   in version control.
-- **Everything is scriptable.** Every menu item, timeline drag and property edit goes through one
-  command registry, so the same actions are reachable from a command line, a JSON control
-  channel and an MCP server for agents.
+- **Everything is scriptable.** Menu actions, timeline edits and property changes are exposed as
+  commands. Engine commands are available through the CLI, JSON control channel and MCP;
+  UI-only commands use the frontend dispatcher and can be invoked through the control channel
+  or an attached MCP bridge.
 - **No FFmpeg.** Video and audio decoding and encoding are pure Rust: FilmCraft's codecs and
   EffectCraft's own VP9, AV1, HEVC and Opus encoders.
 
@@ -126,7 +127,7 @@ or into the Timeline, between layers and at the time you point to.
 
 ## Effects
 
-306 built-in effects across its categories, each with its parameter names, order and
+308 built-in effects across its categories, each with its parameter names, order and
 defaults: blur and sharpen, channel, color correction (Curves, Levels, Hue/Saturation, a full
 color-grading panel…), distort (Warp, Bulge, Turbulent Displace, CC Power Pin…), generate (Fractal Noise,
 Gradient Ramp, Stroke, Write-on, Audio Spectrum…), keying, matte, noise and grain, perspective,
@@ -173,8 +174,10 @@ cannot express; File ▸ Import ▸ Lottie… opens one as a new composition.
 
 ## Built for agents
 
-Everything you can do from a menu is a command with an id, and agents can reach every one of
-them:
+Engine commands are available through the CLI, JSON control channel and MCP. UI-only commands
+need the running app's frontend dispatcher: complete menu access requires the app's control
+channel or an attached MCP bridge. Headless MCP sessions expose supported engine commands,
+but not UI-only commands or bridge-only `ui_*` tools.
 
 - **MCP server:** `effectcraft-cli mcp` speaks the Model Context Protocol over stdio, headless
   or bridged to the running app (`--bridge 9877`). Tools cover commands, the project and property
@@ -228,7 +231,7 @@ tests, layering, asset attribution and the WebAssembly build). See [CONTRIBUTING
 ## Where it stands
 
 EffectCraft is young: its first commit was on 1 October 2026. A comprehensive feature set
-exists, including 306 effects, but breadth is not the same as full maturity across every edge
+exists, including 308 effects, but breadth is not the same as full maturity across every edge
 case. Today it's a good place to try things and to tell us what breaks. It isn't yet recommended
 for production client work. In particular:
 
diff --git a/apps/effectcraft-web/Cargo.toml b/apps/effectcraft-web/Cargo.toml
index 28ea2f369..7743347af 100644
--- a/apps/effectcraft-web/Cargo.toml
+++ b/apps/effectcraft-web/Cargo.toml
@@ -37,6 +37,8 @@ js-sys = "0.3"
 web-sys = { version = "0.3", features = [
     "Blob",
     "BlobPropertyBag",
+    "AbortController",
+    "AbortSignal",
     "CssStyleDeclaration",
     "Document",
     "Element",
@@ -51,6 +53,12 @@ web-sys = { version = "0.3", features = [
     "HtmlInputElement",
     "Location",
     "Navigator",
+    "ReadableStream",
+    "ReadableStreamDefaultReader",
+    "Request",
+    "RequestCache",
+    "RequestInit",
+    "Response",
     "Url",
     "UrlSearchParams",
     "Window",
diff --git a/apps/effectcraft-web/src/app.rs b/apps/effectcraft-web/src/app.rs
index 1dcaf1334..60ff2f8d3 100644
--- a/apps/effectcraft-web/src/app.rs
+++ b/apps/effectcraft-web/src/app.rs
@@ -6,7 +6,8 @@ use std::sync::atomic::{AtomicBool, Ordering};
 
 use effectcraft_engine::Session;
 
-use crate::{api, audio, browse, diskcache, files, frames, persist, storage, worker};
+use crate::startup::Startup;
+use crate::{api, audio, browse, config_file, diskcache, files, frames, persist, storage, worker};
 use effectcraft_ui_egui::EffectcraftApp;
 use serde_json::json;
 use wasm_bindgen::prelude::*;
@@ -83,8 +84,12 @@ pub(crate) fn open_or_import(app: &mut EffectcraftApp, paths: Vec<String>) {
 /// The eframe app: the shared EffectCraft UI plus the browser host's per-frame duties.
 pub struct WebApp {
     pub app: EffectcraftApp,
-    /// Keep the session snapshot (off with `?empty`).
+    /// Keep the session snapshot (off with `?empty`; off with an explicit `"demo"` startup until
+    /// the user's own work begins, see `demo_start`).
     pub persist: bool,
+    /// Started on the demo by the config: the snapshot stays off, so the demo never replaces the
+    /// last visit's project, until the user opens a project from a file or edits the demo.
+    pub demo_start: bool,
 }
 
 impl eframe::App for WebApp {
@@ -117,6 +122,11 @@ impl eframe::App for WebApp {
         api::poll_replies();
         // Render Queue outputs written this frame (here or by a worker) → downloads.
         files::flush_downloads();
+        // The user's own work after a demo start is worth keeping too: turn the snapshot on.
+        if self.demo_start && (self.app.session.path.is_some() || self.app.session.is_dirty()) {
+            self.demo_start = false;
+            self.persist = true;
+        }
         // What a reload comes back to.
         if self.persist {
             // The app's monotonic clock: `ctx.input(|i| i.time)` is stale in a logic-only tick.
@@ -223,6 +233,11 @@ pub async fn start(canvas_id: String) -> Result<(), JsValue> {
     };
     api::set_info("storage", json!({"backend": persist::backend(), "entries": stored, "loadMs": t0.elapsed().as_secs_f64() * 1000.0}));
     audio::install_unlock();
+    // `./effectcraft-config.json`: what to open on load.
+    // `?empty` and `?demo` decide by themselves, so they skip the request.
+    let startup = if empty || query_flag("demo") { Startup::default() } else { config_file::startup().await };
+    // An explicit `"demo"` start leaves the saved session alone until the user opens or edits something.
+    let keep_session = !empty && startup.keeps_session();
     browse::restore();
     diskcache::init();
     storage::refresh();
@@ -248,7 +263,7 @@ pub async fn start(canvas_id: String) -> Result<(), JsValue> {
                     // The canvas can't present any more (#225): the page says so over it and
                     // offers a reload, which brings the session back when browser storage keeps it.
                     let lost = gpu_failures.clone();
-                    let kept = !empty && persist::backend() != "memory";
+                    let kept = keep_session && persist::backend() != "memory";
                     rs.device.set_device_lost_callback(move |reason, message| {
                         let message = format!("GPU device lost ({reason:?}): {message}");
                         lost.report(&message, true);
@@ -258,10 +273,11 @@ pub async fn start(canvas_id: String) -> Result<(), JsValue> {
                 let mut session = session();
                 session.load_settings();
                 let recovery = session.begin_recovery();
-                // `?empty`: a blank project; `?demo`: the demo project; otherwise the last visit's
-                // project (the demo on a first visit).
-                let restored = !empty && !query_flag("demo") && persist::restore(&mut session);
-                if !restored && !empty {
+                // `?empty`: a blank project; `?demo`: the demo project; otherwise what the config's
+                // `startup` says (default: the last visit's project, the demo on a first visit).
+                let demo = query_flag("demo");
+                let restored = !empty && !demo && startup.restores() && persist::restore(&mut session);
+                if !restored && !empty && (demo || startup.demo_when_nothing_restored()) {
                     let _ = session.execute("file.openDemoProject", json!({}));
                 }
                 api::set_info("restored", json!(restored));
@@ -287,7 +303,7 @@ pub async fn start(canvas_id: String) -> Result<(), JsValue> {
                 app = app.with_control(rx);
                 let backend = cc.wgpu_render_state.as_ref().map(|rs| format!("{:?}", rs.adapter.get_info().backend));
                 api::set_info("backend", json!(backend));
-                Ok(Box::new(WebApp { app, persist: !empty }))
+                Ok(Box::new(WebApp { app, persist: keep_session, demo_start: !empty && !keep_session }))
             }),
         )
         .await?;
diff --git a/apps/effectcraft-web/src/config_file.rs b/apps/effectcraft-web/src/config_file.rs
new file mode 100644
index 000000000..614d7d4cb
--- /dev/null
+++ b/apps/effectcraft-web/src/config_file.rs
@@ -0,0 +1,73 @@
+//! `./effectcraft-config.json`, fetched once per page load and shared by whoever reads a key.
+
+use std::cell::RefCell;
+
+use wasm_bindgen::{JsCast, closure::Closure};
+use wasm_bindgen_futures::JsFuture;
+
+use crate::startup::{self, Startup};
+
+/// Longest the request and the body read may take (ms); a stalled server must not hold up start-up.
+const TIMEOUT_MS: i32 = 5_000;
+
+thread_local! {
+    /// `None`: not fetched yet; `Some(None)`: no usable file.
+    static FILE: RefCell<Option<Option<Vec<u8>>>> = const { RefCell::new(None) };
+}
+
+/// The config file's bytes, or `None` when it is missing, too large, unreadable or the request
+/// takes longer than [`TIMEOUT_MS`] (the timer aborts the request and covers the body read).
+async fn fetch() -> Option<Vec<u8>> {
+    let win = web_sys::window()?;
+    let ctl = web_sys::AbortController::new().ok()?;
+    let init = web_sys::RequestInit::new();
+    // Always ask the server: the file is the operator's switch, never a cached copy.
+    init.set_cache(web_sys::RequestCache::NoCache);
+    init.set_signal(Some(&ctl.signal()));
+    let on_timeout = Closure::once(move || ctl.abort());
+    let timer = win.set_timeout_with_callback_and_timeout_and_arguments_0(on_timeout.as_ref().unchecked_ref(), TIMEOUT_MS).ok()?;
+    let out = read(&win, &init).await;
+    win.clear_timeout_with_handle(timer);
+    out
+}
+
+/// Fetch the file and read its body chunk by chunk, giving up as soon as it passes `CONFIG_MAX`.
+async fn read(win: &web_sys::Window, init: &web_sys::RequestInit) -> Option<Vec<u8>> {
+    let req = web_sys::Request::new_with_str_and_init("effectcraft-config.json", init).ok()?;
+    let resp: web_sys::Response = JsFuture::from(win.fetch_with_request(&req)).await.ok()?.dyn_into().ok()?;
+    if resp.status() != 200 {
+        return None;
+    }
+    let reader: web_sys::ReadableStreamDefaultReader = resp.body()?.get_reader().unchecked_into();
+    let mut out = Vec::new();
+    loop {
+        let chunk = JsFuture::from(reader.read()).await.ok()?;
+        if js_sys::Reflect::get(&chunk, &"done".into()).ok()?.as_bool() == Some(true) {
+            return Some(out);
+        }
+        let bytes: js_sys::Uint8Array = js_sys::Reflect::get(&chunk, &"value".into()).ok()?.dyn_into().ok()?;
+        if out.len().saturating_add(bytes.length() as usize) > startup::CONFIG_MAX {
+            // Stop the download: the limit is enforced while reading, not after the whole body arrived.
+            let _ = reader.cancel();
+            return None;
+        }
+        out.extend_from_slice(&bytes.to_vec());
+    }
+}
+
+/// The config file's bytes (`None` when there is none), fetched on the first call.
+pub async fn bytes() -> Option<Vec<u8>> {
+    if let Some(done) = FILE.with(|f| f.borrow().clone()) {
+        return done;
+    }
+    let got = fetch().await;
+    FILE.with(|f| *f.borrow_mut() = Some(got.clone()));
+    got
+}
+
+/// The configured startup behaviour.
+pub async fn startup() -> Startup {
+    let s = bytes().await.map(|b| startup::parse(&b)).unwrap_or_default();
+    log::info!("startup: {s:?}");
+    s
+}
diff --git a/apps/effectcraft-web/src/lib.rs b/apps/effectcraft-web/src/lib.rs
index 97d2e887f..e1bf85894 100644
--- a/apps/effectcraft-web/src/lib.rs
+++ b/apps/effectcraft-web/src/lib.rs
@@ -18,10 +18,11 @@
 //! | cpal audio output | Web Audio: an AudioWorklet fed from the preview mixdown (`audio`) |
 //! | TCP control channel / MCP | `window.effectcraft` JavaScript API (`api`) |
 //!
-//! [`store`] is portable (unit-tested natively); everything else is `wasm32`-only.
+//! [`store`] and [`startup`] are portable (unit-tested natively); everything else is `wasm32`-only.
 
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
 
+pub mod startup;
 pub mod store;
 
 #[cfg(target_arch = "wasm32")]
@@ -33,6 +34,8 @@ pub mod audio;
 #[cfg(target_arch = "wasm32")]
 pub mod browse;
 #[cfg(target_arch = "wasm32")]
+pub mod config_file;
+#[cfg(target_arch = "wasm32")]
 pub mod diskcache;
 #[cfg(target_arch = "wasm32")]
 pub mod files;
diff --git a/apps/effectcraft-web/src/startup.rs b/apps/effectcraft-web/src/startup.rs
new file mode 100644
index 000000000..4759096f3
--- /dev/null
+++ b/apps/effectcraft-web/src/startup.rs
@@ -0,0 +1,55 @@
+//! The `startup` key of `./effectcraft-config.json`: which project the page opens on load.
+//!
+//! | Value | On load |
+//! |---|---|
+//! | `"last"` (and absent) | the last visit's project; the demo project on a first visit |
+//! | `"empty"` | the last visit's project; a blank project on a first visit, never the demo |
+//! | `"demo"` | the demo project, whatever the last visit left |
+//!
+//! The `?empty` and `?demo` URL flags still win. Anything else (a missing key, another type, an
+//! unknown value, a config that is not JSON) is the default, `"last"`.
+
+use serde_json::Value;
+
+/// What the page opens on load.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum Startup {
+    #[default]
+    Last,
+    Empty,
+    Demo,
+}
+
+/// The largest config file read (bytes).
+pub const CONFIG_MAX: usize = 64 * 1024;
+
+/// The `startup` key of a config file's bytes.
+pub fn parse(bytes: &[u8]) -> Startup {
+    if bytes.len() > CONFIG_MAX {
+        return Startup::default();
+    }
+    let Ok(v) = serde_json::from_slice::<Value>(bytes) else { return Startup::default() };
+    match v.get("startup").and_then(Value::as_str) {
+        Some("empty") => Startup::Empty,
+        Some("demo") => Startup::Demo,
+        _ => Startup::Last,
+    }
+}
+
+impl Startup {
+    /// Whether the last visit's project is restored (off for the demo).
+    pub fn restores(self) -> bool {
+        self != Startup::Demo
+    }
+
+    /// Whether the session snapshot keeps being saved (off for the demo, so it never replaces the
+    /// project the last visit left).
+    pub fn keeps_session(self) -> bool {
+        self != Startup::Demo
+    }
+
+    /// Whether the demo project opens when nothing was restored (off for a blank start).
+    pub fn demo_when_nothing_restored(self) -> bool {
+        self != Startup::Empty
+    }
+}
diff --git a/apps/effectcraft-web/tests/it/main.rs b/apps/effectcraft-web/tests/it/main.rs
new file mode 100644
index 000000000..a4d242ba5
--- /dev/null
+++ b/apps/effectcraft-web/tests/it/main.rs
@@ -0,0 +1 @@
+mod startup_tests;
diff --git a/apps/effectcraft-web/tests/it/startup_tests.rs b/apps/effectcraft-web/tests/it/startup_tests.rs
new file mode 100644
index 000000000..3ce90569c
--- /dev/null
+++ b/apps/effectcraft-web/tests/it/startup_tests.rs
@@ -0,0 +1,52 @@
+//! The `startup` key of the config file.
+
+use effectcraft_web::startup::{CONFIG_MAX, Startup, parse};
+
+/// The three accepted values parse.
+#[test]
+fn the_three_values() {
+    assert_eq!(parse(br#"{"startup":"empty"}"#), Startup::Empty);
+    assert_eq!(parse(br#"{"startup":"demo"}"#), Startup::Demo);
+    assert_eq!(parse(br#"{"startup":"last"}"#), Startup::Last);
+}
+
+/// A missing key, a wrong type, an unknown value or a non-object file gives `Last`.
+#[test]
+fn absent_or_invalid_is_the_default() {
+    for bytes in
+        [&b"{}"[..], b"", b"not json", b"[]", b"null", br#"{"startup":1}"#, br#"{"startup":"Empty"}"#, br#"{"startup":null}"#, br#"{"startup":["empty"]}"#]
+    {
+        assert_eq!(parse(bytes), Startup::Last, "{:?}", String::from_utf8_lossy(bytes));
+    }
+}
+
+/// Other keys do not hide `startup`.
+#[test]
+fn a_config_with_other_keys_still_has_its_startup() {
+    assert_eq!(parse(br#"{"remote":{"mounts":[]},"startup":"empty"}"#), Startup::Empty);
+    assert_eq!(parse(br#"{"startup":"demo","unknown":{"a":1}}"#), Startup::Demo);
+}
+
+/// A file over `CONFIG_MAX` is ignored.
+#[test]
+fn an_oversized_file_is_the_default() {
+    let mut big = br#"{"startup":"empty","pad":""#.to_vec();
+    big.extend(std::iter::repeat_n(b'x', CONFIG_MAX));
+    big.extend_from_slice(br#""}"#);
+    assert_eq!(parse(&big), Startup::Last);
+}
+
+/// Which project each value restores or opens.
+#[test]
+fn what_each_value_does_on_load() {
+    assert!(Startup::Last.restores() && Startup::Last.demo_when_nothing_restored());
+    assert!(Startup::Empty.restores() && !Startup::Empty.demo_when_nothing_restored());
+    assert!(!Startup::Demo.restores() && Startup::Demo.demo_when_nothing_restored());
+}
+
+/// Only the explicit demo start stops saving the session.
+#[test]
+fn only_the_demo_start_leaves_the_saved_session_alone() {
+    assert!(Startup::Last.keeps_session() && Startup::Empty.keeps_session());
+    assert!(!Startup::Demo.keeps_session());
+}
diff --git a/apps/effectcraft-web/web/sw.js b/apps/effectcraft-web/web/sw.js
index 4acbeeeeb..8f48a93bc 100644
--- a/apps/effectcraft-web/web/sw.js
+++ b/apps/effectcraft-web/web/sw.js
@@ -3,7 +3,8 @@
 // `cargo xtask web` fills in the build's file list and version. Every file is precached into a
 // cache named after the version, served cache-first (responses keep the server's headers, so
 // the page stays cross-origin isolated: COOP/COEP), and old versions are dropped once the new
-// one activates. Anything else same-origin is fetched from the network and cached for next time.
+// one activates. Anything else same-origin is fetched from the network and cached for next time,
+// except the config file, which must stay live.
 const VERSION = "__EC_VERSION__";
 const FILES = __EC_FILES__;
 const CACHE = `effectcraft-${VERSION}`;
@@ -30,6 +31,7 @@ self.addEventListener("fetch", (event) => {
   const req = event.request;
   const url = new URL(req.url);
   if (req.method !== "GET" || url.origin !== self.location.origin) return;
+  if (url.pathname.endsWith("/effectcraft-config.json")) return;
   event.respondWith(
     (async () => {
       const cache = await caches.open(CACHE).catch(() => null);
diff --git a/crates/automation/tests/qa/compositing.rs b/crates/automation/tests/qa/compositing.rs
index da78ae116..d5de8f687 100644
--- a/crates/automation/tests/qa/compositing.rs
+++ b/crates/automation/tests/qa/compositing.rs
@@ -35,7 +35,7 @@ fn import_footage(qa: &mut Qa) -> (Value, Value) {
     // Footage: the sequence, and a layered PSD written by the app itself (Save Frame As ▸
     // Photoshop Layers) from a small comp.
     let seq = write_sequence(qa);
-    let imp = qa.exec("file.import", json!({"paths": [seq]}));
+    let imp = qa.exec("file.import", json!({"paths": [seq], "sequence": true}));
     let seq_item = imp["items"][0].clone();
     let project = qa.tool("get_project", json!({}));
     let it = project["items"].as_array().unwrap().iter().find(|i| i["id"] == seq_item).unwrap().clone();
diff --git a/crates/automation/tests/qa/tracking.rs b/crates/automation/tests/qa/tracking.rs
index 837872658..ee6bbb2e9 100644
--- a/crates/automation/tests/qa/tracking.rs
+++ b/crates/automation/tests/qa/tracking.rs
@@ -52,7 +52,7 @@ fn shake_offset(f: u32) -> (i64, i64) {
 
 /// Import a sequence at 12 fps and make a comp of it; returns (comp, layer).
 fn plate_comp(qa: &mut Qa, first: &str, name: &str) -> (Value, Value) {
-    let item = qa.exec("file.import", json!({"paths": [first]}))["items"][0].clone();
+    let item = qa.exec("file.import", json!({"paths": [first], "sequence": true}))["items"][0].clone();
     qa.exec("file.interpretFootage", json!({"items": [item.clone()], "frameRate": 12}));
     let comp = qa.exec("comp.new", json!({"name": name, "width": 160, "height": 90, "frameRate": 12, "duration": 1}))["comp"].clone();
     let layer = qa.exec("layer.addItem", json!({"item": item}))["layer"].clone();
diff --git a/crates/av1enc/src/decide.rs b/crates/av1enc/src/decide.rs
index eb108a204..d8bc1f825 100644
--- a/crates/av1enc/src/decide.rs
+++ b/crates/av1enc/src/decide.rs
@@ -174,6 +174,8 @@ pub(crate) struct Decider<'a> {
     ac_q: f32,
     dc_qi: i64,
     ac_qi: i64,
+    /// Smallest magnitude that quantises to a non-zero level, `[dc, ac][intra]`.
+    dead_zone: [[f32; 2]; 2],
     lambda: f64,
     lambda_sad: f64,
     /// Half-sample interpolations of the reference luma (visible area): (8, 0), (0, 8), (8, 8).
@@ -183,6 +185,9 @@ pub(crate) struct Decider<'a> {
 }
 
 const MODE_BITS_INTRA: f64 = 3.0;
+/// Dead-zone quantiser rounding offsets (below one half) for inter and intra blocks.
+const INTER_RND: f32 = 0.30;
+const INTRA_RND: f32 = 0.38;
 
 impl<'a> Decider<'a> {
     pub fn new(g: &'a FrameGeom, bd: u32, qidx: u8, intra_only: bool, src: &'a [Plane; 3], refr: Option<&'a RefFrame>) -> Self {
@@ -209,6 +214,7 @@ impl<'a> Decider<'a> {
             ac_q: ac_qi as f32,
             dc_qi,
             ac_qi,
+            dead_zone: [dc_qi, ac_qi].map(|q| [INTER_RND, INTRA_RND].map(|rnd| zero_threshold(q as f32, rnd))),
             lambda,
             lambda_sad: lambda.sqrt(),
             half: match refr {
@@ -577,8 +583,9 @@ impl<'a> Decider<'a> {
             let (dy, dx) = (m[0] >> 3, m[1] >> 3);
             dx >= lim_x.0 && dx <= lim_x.1 && dy >= lim_y.0 && dy <= lim_y.1
         };
+        let lg = log2_table();
         let mv_bits = |m: [i32; 2]| -> f64 {
-            let comp = |d: i32| if d == 0 { 0.5 } else { 2.0 + 2.0 * ((d.abs() / 8) as f64 + 1.0).log2() };
+            let comp = |d: i32| if d == 0 { 0.5 } else { 2.0 + 2.0 * log2_of(lg, (d.abs() / 8) as usize + 1) };
             comp(m[0] - pred_mv[0]) + comp(m[1] - pred_mv[1])
         };
         let cost =
@@ -863,12 +870,18 @@ impl<'a> Decider<'a> {
         }
         forward_2d(res, coef, n, tx_type);
         // dead-zone quantiser: rounding offset below one half
-        let rnd = if intra { 0.38f32 } else { 0.30f32 };
+        let rnd = if intra { INTRA_RND } else { INTER_RND };
+        let [dc_thr, ac_thr] = [self.dead_zone[0][intra as usize], self.dead_zone[1][intra as usize]];
         levels.fill(0);
         let mut nonzero = false;
         for (k, (&cf, l)) in coef.iter().zip(levels.iter_mut()).enumerate() {
-            let q = if k == 0 { self.dc_q } else { self.ac_q };
-            let a = (cf.abs() / q + rnd).floor() as i32;
+            let (q, thr) = if k == 0 { (self.dc_q, dc_thr) } else { (self.ac_q, ac_thr) };
+            // dead zone: below the exact threshold the level is zero, no division needed
+            if cf.abs() < thr {
+                continue;
+            }
+            // the operand is >= 0, so truncation equals floor
+            let a = (cf.abs() / q + rnd) as i32;
             if a != 0 {
                 *l = if cf < 0.0 { -a.min(1 << 16) } else { a.min(1 << 16) };
                 nonzero = true;
@@ -913,6 +926,33 @@ impl<'a> Decider<'a> {
     }
 }
 
+/// Smallest `x >= 0` with `(x / q + rnd) as i32 >= 1` in f32 arithmetic. The expression is
+/// monotone in `x`, so a binary search over the bit patterns finds the exact boundary.
+fn zero_threshold(q: f32, rnd: f32) -> f32 {
+    let (mut lo, mut hi) = (0u32, f32::MAX.to_bits());
+    while lo < hi {
+        let mid = lo + (hi - lo) / 2;
+        if (f32::from_bits(mid) / q + rnd) as i32 >= 1 {
+            hi = mid;
+        } else {
+            lo = mid + 1;
+        }
+    }
+    f32::from_bits(lo)
+}
+
+const LOG2_TABLE_LEN: usize = 1025;
+
+/// `log2(i)` for `i < LOG2_TABLE_LEN`, computed with the same `f64::log2` call as the direct form.
+fn log2_table() -> &'static [f64; LOG2_TABLE_LEN] {
+    static TABLE: std::sync::OnceLock<[f64; LOG2_TABLE_LEN]> = std::sync::OnceLock::new();
+    TABLE.get_or_init(|| std::array::from_fn(|i| (i as f64).log2()))
+}
+
+fn log2_of(table: &[f64; LOG2_TABLE_LEN], v: usize) -> f64 {
+    if v < LOG2_TABLE_LEN { table[v] } else { (v as f64).log2() }
+}
+
 /// Unnormalised Walsh-Hadamard transform of 4 or 8 values, in place.
 fn hadamard(v: &mut [i32]) {
     let n = v.len();
@@ -941,13 +981,14 @@ fn estimate_bits(levels: &[i32], tx_sz: usize) -> f64 {
     if eob == 0 {
         return 1.0;
     }
-    let mut bits = 3.0 + (eob as f64).log2();
+    let lg = log2_table();
+    let mut bits = 3.0 + log2_of(lg, eob);
     for &pos in &scan[..eob] {
         let a = levels[pos as usize].unsigned_abs();
         bits += match a {
             0 => 0.7,
             1 => 2.5,
-            _ => 3.5 + 1.6 * (a as f64).log2(),
+            _ => 3.5 + 1.6 * log2_of(lg, a as usize),
         };
     }
     bits
@@ -961,3 +1002,64 @@ pub(crate) fn scan_for(tx_sz: usize) -> &'static [u16] {
         _ => &DEFAULT_SCAN_32X32,
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tables::{AC_QLOOKUP, DC_QLOOKUP};
+
+    /// The quantiser as it was before the dead-zone threshold and the truncation.
+    fn quant_ref(cf: f32, q: f32, rnd: f32) -> i32 {
+        (cf.abs() / q + rnd).floor() as i32
+    }
+
+    fn quant_new(cf: f32, q: f32, rnd: f32, thr: f32) -> i32 {
+        if cf.abs() < thr {
+            return 0;
+        }
+        (cf.abs() / q + rnd) as i32
+    }
+
+    #[test]
+    fn dead_zone_threshold_is_exact() {
+        let mut state = 0x1234_5678_9abc_def0u64;
+        let mut next = move || {
+            state ^= state << 13;
+            state ^= state >> 7;
+            state ^= state << 17;
+            state
+        };
+        for table in AC_QLOOKUP.iter().chain(DC_QLOOKUP.iter()) {
+            for &qi in table.iter() {
+                let q = qi as f32;
+                for rnd in [INTER_RND, INTRA_RND] {
+                    let thr = zero_threshold(q, rnd);
+                    // the boundary itself and its neighbours
+                    let b = thr.to_bits();
+                    for bits in b.saturating_sub(3)..=b + 3 {
+                        let cf = f32::from_bits(bits);
+                        assert_eq!(quant_ref(cf, q, rnd), quant_new(cf, q, rnd, thr), "q {q} rnd {rnd} cf {cf}");
+                        assert_eq!(quant_ref(-cf, q, rnd), quant_new(-cf, q, rnd, thr));
+                    }
+                    for _ in 0..200 {
+                        let cf = f32::from_bits((next() >> 32) as u32 & 0x7fff_ffff);
+                        if cf.is_nan() {
+                            continue;
+                        }
+                        assert_eq!(quant_ref(cf, q, rnd), quant_new(cf, q, rnd, thr));
+                        let cf = (next() % 100_000) as f32 / 100.0;
+                        assert_eq!(quant_ref(cf, q, rnd), quant_new(cf, q, rnd, thr));
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn log2_table_matches_direct_log2() {
+        let t = log2_table();
+        for v in 1..3000usize {
+            assert_eq!(log2_of(t, v).to_bits(), (v as f64).log2().to_bits(), "{v}");
+        }
+    }
+}
diff --git a/crates/effects/src/audio_fx.rs b/crates/effects/src/audio_fx.rs
index cd9153d66..2aab70309 100644
--- a/crates/effects/src/audio_fx.rs
+++ b/crates/effects/src/audio_fx.rs
@@ -206,6 +206,12 @@ pub fn reverses(id: &str) -> bool {
     id == "ec.audio.backwards"
 }
 
+/// Does each output sample depend only on the input sample at the same time (no state), so the
+/// mixer may run the effect in short pieces with parameters animated between them?
+pub fn per_sample(id: &str) -> bool {
+    matches!(id, "ec.audio.stereomixer" | "ec.audio.backwards")
+}
+
 /// Seconds of input history the effect needs before a block to reach the state it would have
 /// had when processing continuously.
 pub fn preroll(id: &str, params: &Params) -> f64 {
diff --git a/crates/effects/src/catalog.rs b/crates/effects/src/catalog.rs
index 80a937b22..85be739ed 100644
--- a/crates/effects/src/catalog.rs
+++ b/crates/effects/src/catalog.rs
@@ -182,6 +182,20 @@ mod tests {
         assert!(have == want, "docs/effects.md is stale: UPDATE_DOCS=1 cargo test -p effectcraft-effects --lib effects_doc_is_current");
     }
 
+    /// The README quotes the number of effects (#2565): every count it gives is the registry's.
+    #[test]
+    fn readme_effect_counts_are_current() {
+        let readme = std::fs::read_to_string(concat!(env!("CARGO_MANIFEST_DIR"), "/../../README.md")).unwrap_or_default();
+        let words: Vec<&str> = readme.split_whitespace().collect();
+        let counts: Vec<&str> = words
+            .windows(3)
+            .filter(|w| w[0].parse::<u32>().is_ok() && (w[1].starts_with("effects") || (w[1] == "built-in" && w[2].starts_with("effects"))))
+            .map(|w| w[0])
+            .collect();
+        let n = super::registry().len().to_string();
+        assert!(!counts.is_empty() && counts.iter().all(|c| *c == n), "README.md says {counts:?} effects; the registry has {n}");
+    }
+
     #[test]
     fn cpu_only_controls_keep_effects_off_the_gpu() {
         use effectcraft_keyframe::Value;
diff --git a/crates/effects/src/channel3d.rs b/crates/effects/src/channel3d.rs
index 08241107c..dc65c3255 100644
--- a/crates/effects/src/channel3d.rs
+++ b/crates/effects/src/channel3d.rs
@@ -7,6 +7,11 @@
 //! pass for a precomp of a 3D comp. Without auxiliary channels they pass the layer through
 //! (EXtractoR still maps the layer's own R, G, B and A).
 //!
+//! 3D Layer Instance (Create 3D Layer Instance's own effect, Layer ▸ Create) is not an aux
+//! reader: it replaces the layer's pixels with a referenced layer's render — for a 3D model
+//! layer, its render on its own through the comp's camera — so 2D effects can be applied to a
+//! 3D layer's render.
+//!
 //! Aux pixels are looked up nearest-neighbour (IDs must not be interpolated) at each buffer
 //! pixel's layer position, so render scale and layer padding are respected.
 
@@ -582,6 +587,19 @@ fn extractor(ctx: &EffectCtx, mut b: Buf) -> Buf {
     b
 }
 
+/// A 2D copy of a referenced layer (Create 3D Layer Instance's solid): the layer's pixels
+/// replaced with the referenced layer's render, alpha included — the copy is transparent
+/// where the referenced layer isn't. A 3D model or primitive layer is rendered on its own
+/// through the comp's camera, as After Effects renders 3D layers; another layer is read with
+/// its masks and effects. With no layer chosen the effect passes the layer through, as a layer
+/// parameter with nothing chosen does.
+fn instance_3d(ctx: &EffectCtx, mut b: Buf) -> Buf {
+    if let Some(o) = ctx.layer_param("layer", true) {
+        b.img = crate::util::fit_layer(ctx, &b, &o, false);
+    }
+    b
+}
+
 pub fn specs() -> Vec<EffectSpec> {
     let text = |id: &'static str, name: &'static str, d: &str| p(id, name, Value::Str(d.into()), ParamUi::Text);
     vec![
@@ -682,6 +700,7 @@ pub fn specs() -> Vec<EffectSpec> {
             ],
             identifier,
         ),
+        spec("ec.3d.instance3d", "3D Layer Instance", vec![p("layer", "Layer", Value::Layer(None), ParamUi::Layer)], instance_3d),
     ]
 }
 
diff --git a/crates/effects/src/channel3d/tests.rs b/crates/effects/src/channel3d/tests.rs
index 4fc84440e..e69c2a6aa 100644
--- a/crates/effects/src/channel3d/tests.rs
+++ b/crates/effects/src/channel3d/tests.rs
@@ -373,3 +373,29 @@ fn channel_extract_antialias_averages_sub_pixels() {
     let soft = run("ec.3d.channelextract", &[vals.as_slice(), &[("antialias", Value::Bool(true))]].concat(), &host);
     assert!((soft.get(5, 5)[0] - 0.5).abs() < 1e-5, "{:?}", soft.get(5, 5));
 }
+
+#[test]
+fn instance3d_replaces_the_pixels_with_the_referenced_layer() {
+    // Create 3D Layer Instance's copy: the chosen layer's render takes the place of the layer's
+    // own pixels, alpha included — the copy is transparent where the referenced layer isn't —
+    // and with no layer chosen the layer passes through.
+    struct Host(Image);
+    impl EffectHost for Host {
+        fn layer(&self, id: u64, _: bool) -> Option<LayerPixels> {
+            (id == 7).then(|| LayerPixels { buf: Buf { img: self.0.clone(), offset: [0.0; 2], scale: 1.0 }, size: [self.0.width as f64, self.0.height as f64] })
+        }
+        fn audio(&self, _: u64, _: f64, _: usize, _: u32) -> Option<Vec<f32>> {
+            None
+        }
+    }
+    let solid = || Image::filled(4, 4, [1.0, 1.0, 1.0, 1.0]);
+    let mut render = Image::new(4, 4);
+    render.set(1, 1, [1.0, 0.0, 0.0, 1.0]);
+    let env = EffectEnv { host: Some(&Host(render)), ..Default::default() };
+    let out = run_fx("ec.3d.instance3d", &[("layer", Value::Layer(Some(7)))], solid(), 0.0, env);
+    assert_eq!(out.img.get(1, 1), [1.0, 0.0, 0.0, 1.0], "the referenced layer's pixel");
+    assert_eq!(out.img.get(3, 3), [0.0; 4], "transparent where the referenced layer isn't");
+    // No layer chosen: the layer's own pixels.
+    let out = run_fx("ec.3d.instance3d", &[], solid(), 0.0, EffectEnv::default());
+    assert_eq!(out.img.data, solid().data);
+}
diff --git a/crates/effects/src/lib.rs b/crates/effects/src/lib.rs
index 32e662fec..117506807 100644
--- a/crates/effects/src/lib.rs
+++ b/crates/effects/src/lib.rs
@@ -312,17 +312,34 @@ impl Buf {
         self.offset[0] += l as f64;
         self.offset[1] += t as f64;
     }
-    /// Grow by `pad` transparent pixels on every side.
+    /// Grow by `pad` transparent pixels on every side, within [`pad_within_budget`] and as
+    /// clamped by [`Image::effective_pad`].
     pub fn pad(&mut self, pad: u32) {
-        if pad == 0 {
+        let eff = self.img.effective_pad(pad_within_budget(self.img.width, self.img.height, pad));
+        if eff == 0 {
             return;
         }
-        self.img = self.img.padded(pad);
-        self.offset[0] += pad as f64;
-        self.offset[1] += pad as f64;
+        self.img = self.img.padded(eff);
+        self.offset[0] += eff as f64;
+        self.offset[1] += eff as f64;
     }
 }
 
+/// `pad` on every side of a `w` × `h` effect buffer, cut so the padded buffer stays within
+/// 16 Mpx (256 MiB of f32 RGBA) or four times its own area, whichever is larger: a small layer
+/// far from an effect's centre can't ask for gigabytes (#2261). Shared with the GPU path.
+pub fn pad_within_budget(w: u32, h: u32, pad: u32) -> u32 {
+    const MIN_BUDGET: f64 = 16_777_216.0;
+    let (w, h) = (f64::from(w), f64::from(h));
+    let budget = MIN_BUDGET.max(4.0 * w * h);
+    if (w + 2.0 * f64::from(pad)) * (h + 2.0 * f64::from(pad)) <= budget {
+        return pad;
+    }
+    // (w + 2p)(h + 2p) = budget, solved for p.
+    let p = (((w - h).powi(2) + 4.0 * budget).sqrt() - (w + h)) / 4.0;
+    (p.floor().max(0.0) as u32).min(pad)
+}
+
 /// Motion Tile's output frame for a buffer with layer origin `offset` (pixels) at `scale`:
 /// `(width, height, offset)`. Output Width / Height grow (or crop) the layer rectangle about its
 /// centre, on adjustment layers too, where the rectangle is the comp's and starts at the comp
@@ -1344,6 +1361,23 @@ pub(crate) fn run_fx(id: &str, vals: &[(&str, Value)], img: Image, time: f64, en
 mod tests {
     use super::*;
 
+    /// #2261: a 20 × 20 layer with CC Radial Fast Blur's Center far away grows to at most 16 Mpx;
+    /// big layers may still grow to four times their area, and small pads are untouched.
+    #[test]
+    fn padded_buffers_stay_within_the_budget() {
+        let area = |w: u32, h: u32, p: u32| (u64::from(w) + 2 * u64::from(p)) * (u64::from(h) + 2 * u64::from(p));
+        let far = radial_fast_pad((6500.0, 6500.0), 20, 20, 0.8);
+        assert_eq!(far, 4096, "the effect asks for its full pad");
+        let mut b = Buf { img: Image::new(20, 20), offset: [0.0; 2], scale: 1.0 };
+        b.pad(far);
+        assert!(area(20, 20, 0) < area(b.img.width, b.img.height, 0) && area(b.img.width, b.img.height, 0) <= 1 << 24, "{}x{}", b.img.width, b.img.height);
+        assert_eq!(b.offset, [f64::from((b.img.width - 20) / 2); 2], "the content keeps its place");
+        let p = pad_within_budget(3840, 2160, 4096);
+        assert!(p > 1000 && area(3840, 2160, p) <= 4 * 3840 * 2160 && area(3840, 2160, p + 1) > 4 * 3840 * 2160);
+        assert_eq!(pad_within_budget(640, 360, 200), 200);
+        assert_eq!(pad_within_budget(20, 20, 0), 0);
+    }
+
     #[test]
     fn run_fx_passthrough() {
         let img = Image::filled(4, 3, [0.5, 0.25, 0.125, 1.0]);
@@ -1351,6 +1385,20 @@ mod tests {
         assert_eq!(out.img.data, img.data);
     }
 
+    #[test]
+    fn pad_offset_follows_the_clamped_pad() {
+        // Image::padded clamps a hostile pad to keep each side within MAX_PADDED_SIDE; the offset
+        // must move by the pad actually applied, or the content drifts from its layer position.
+        let mut img = Image::new(29_990, 2);
+        img.set(0, 0, [1.0, 0.0, 0.0, 1.0]);
+        let mut buf = Buf { img, offset: [3.0, 4.0], scale: 1.0 };
+        buf.pad(u32::MAX);
+        // Width binds: (MAX_PADDED_SIDE - 29 990) / 2 = 5.
+        assert_eq!(buf.offset, [8.0, 9.0]);
+        let (x, y) = buf.to_px([-3.0, -4.0]);
+        assert_eq!(buf.img.get(x as i64, y as i64), [1.0, 0.0, 0.0, 1.0]);
+    }
+
     #[test]
     #[ignore]
     fn dump_registry() {
diff --git a/crates/engine/presets/text_animators.json b/crates/engine/presets/text_animators.json
index 20e142268..e82707a52 100644
--- a/crates/engine/presets/text_animators.json
+++ b/crates/engine/presets/text_animators.json
@@ -77,7 +77,7 @@
           "name": "Tracking In",
           "properties": { "tracking": 0, "opacity": 100 },
           "keys": {
-            "tracking": [[0, 400], [1.6, 0]],
+            "tracking": [[0, 40], [1.6, 0]],
             "opacity": [[0, 0], [0.8, 100]]
           },
           "ease": true,
diff --git a/crates/engine/src/analysis/tracking.rs b/crates/engine/src/analysis/tracking.rs
index 434cdd8af..fe04f882b 100644
--- a/crates/engine/src/analysis/tracking.rs
+++ b/crates/engine/src/analysis/tracking.rs
@@ -207,7 +207,7 @@ pub(crate) fn source_frame(
     t: Tick,
     expr: Option<&dyn ExprHost>,
 ) -> Option<(Arc<Image>, [f64; 2])> {
-    let ctx = EvalCtx { project, comp_id: cid, comp, time: t, expr, footage: None };
+    let ctx = EvalCtx { project, comp_id: cid, comp, time: t, expr, footage: None, property_overrides: &[], media_overrides: &[] };
     if let effectcraft_project::LayerSource::Footage { item } = &layer.source
         && let Some(effectcraft_project::ItemKind::Footage(f)) = project.item(*item).map(|i| &i.kind)
         && f.has_video
diff --git a/crates/engine/src/cmd/app_more.rs b/crates/engine/src/cmd/app_more.rs
index f607c8288..5bd897ba9 100644
--- a/crates/engine/src/cmd/app_more.rs
+++ b/crates/engine/src/cmd/app_more.rs
@@ -152,7 +152,7 @@ fn clear_recent_presets(s: &mut Session, _: &Value) -> Result<Value> {
 
 fn save_copy_xml(s: &mut Session, p: &Value) -> Result<Value> {
     let path = str_p(p, "path").ok_or_else(|| bad("file.saveCopyAsXml", "missing `path` (.ecprojx)"))?;
-    let xml = crate::xml_project::to_xml(&s.project.to_file_json_with_view(&s.saved_view())?).map_err(EngineError::Other)?;
+    let xml = crate::xml_project::to_xml(&s.project.to_file_json_with_view(&s.saved_view(), false)?).map_err(EngineError::Other)?;
     s.services.write_file(path, xml.as_bytes()).map_err(|e| EngineError::Other(format!("cannot write {path}: {e}")))?;
     s.toast(format!("Saved an XML copy to {path}"));
     Ok(json!({"path": path, "bytes": xml.len()}))
diff --git a/crates/engine/src/cmd/comp_more.rs b/crates/engine/src/cmd/comp_more.rs
index d6de320ec..478dc8259 100644
--- a/crates/engine/src/cmd/comp_more.rs
+++ b/crates/engine/src/cmd/comp_more.rs
@@ -5,7 +5,7 @@ use effectcraft_project::Marker;
 use effectcraft_time::Tick;
 use serde_json::{Value, json};
 
-use super::{CommandSpec, always, bad, comp_id, f_p, has_comp, has_layers, layers_p, str_p};
+use super::{CommandSpec, always, b_p, bad, comp_id, f_p, has_comp, has_layers, layers_p, str_p};
 use crate::prefs::CompPreset;
 use crate::{EngineError, Result, Session, cmd, query};
 
@@ -82,7 +82,7 @@ pub(crate) fn encode_png(rgba: &[u8], w: u32, h: u32) -> std::result::Result<Vec
 /// Save Frame As ▸ File with `queue`: a Render Queue item for the current frame, from the Frame
 /// Default templates (Edit ▸ Templates).
 fn queue_frame(s: &mut Session, p: &Value) -> Result<Value> {
-    use effectcraft_project::render_queue::{RenderQueueItem, TimeSpan};
+    use effectcraft_project::render_queue::{Channels, RenderQueueItem, TimeSpan};
     use effectcraft_project::render_templates::TemplateSlot;
     let cid = comp_id(s, p)?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
@@ -91,6 +91,9 @@ fn queue_frame(s: &mut Session, p: &Value) -> Result<Value> {
     it.settings = s.project.render_templates.default_render_settings(TemplateSlot::Still);
     it.settings.time_span = TimeSpan::Custom { start: t, end: t + comp.frame_duration() };
     it.output = s.project.render_templates.default_output_module(TemplateSlot::Still);
+    if b_p(p, "transparent") == Some(false) {
+        it.output.channels = Channels::Rgb;
+    }
     if let Some(path) = str_p(p, "path") {
         it.output.output = path.to_string();
     } else if !it.output.format.is_sequence() {
@@ -107,7 +110,7 @@ fn queue_frame(s: &mut Session, p: &Value) -> Result<Value> {
 }
 
 fn save_frame(s: &mut Session, p: &Value) -> Result<Value> {
-    if p.get("queue").and_then(Value::as_bool) == Some(true) {
+    if b_p(p, "queue") == Some(true) {
         return queue_frame(s, p);
     }
     let path = str_p(p, "path").ok_or_else(|| bad("comp.saveFrameAs", "missing `path` (.png)"))?.to_string();
@@ -117,7 +120,7 @@ fn save_frame(s: &mut Session, p: &Value) -> Result<Value> {
     let scale = f_p(p, "scale").unwrap_or(1.0).clamp(0.01, 4.0);
     let bg = comp.background;
     let img = s.render(cid, t, effectcraft_render::RenderOpts { scale, backend: effectcraft_render::Backend::Auto, ..Default::default() });
-    let rgba = img.to_rgba8_over(bg);
+    let rgba = if b_p(p, "transparent") == Some(false) { img.to_rgba8_over(bg) } else { img.to_rgba8() };
     let png = encode_png(&rgba, img.width, img.height).map_err(|e| EngineError::Other(format!("PNG encoding failed: {e}")))?;
     s.services.write_file(&path, &png).map_err(|e| EngineError::Other(format!("cannot write {path}: {e}")))?;
     s.toast(format!("Saved frame to {path}"));
@@ -235,7 +238,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "File...",
             ["Composition", "Save Frame As"],
             Some("Cmd+Alt+S"),
-            "{path (.png; with queue: an output path or template), time?, scale?, queue?: bool (add a Render Queue item from the Frame Default templates instead of writing now)}",
+            "{path (.png; with queue: an output path or template), time?, scale?, queue?: bool (add a Render Queue item from the Frame Default templates instead of writing now), transparent?: bool (default true)}",
             has_comp,
             save_frame
         ),
diff --git a/crates/engine/src/cmd/create.rs b/crates/engine/src/cmd/create.rs
index 850d38ada..6c4b02c87 100644
--- a/crates/engine/src/cmd/create.rs
+++ b/crates/engine/src/cmd/create.rs
@@ -1,14 +1,17 @@
 //! Layer ▸ Create: Convert to Editable Text (Photoshop type layers), Create Shapes from Text,
-//! Create Masks from Text and Create Shapes from Vector Layer (SVG footage).
+//! Create Masks from Text, Create Shapes from Vector Layer (SVG footage) and Create 3D Layer
+//! Instance (a 2D copy of a 3D model layer that 2D effects can be applied to).
 
 use effectcraft_color::Label;
+use effectcraft_keyframe::Value as KV;
+use effectcraft_project::build::{self, Ids};
 use effectcraft_project::{ItemKind, LayerSource, Solid};
 use serde_json::{Value, json};
 
 use super::{CommandSpec, bad, has_layers, layers_p, str_p};
 use crate::{EngineError, Result, Session, cmd};
 
-const OPS: &str = "editableText|shapesFromText|masksFromText|shapesFromVector";
+const OPS: &str = "editableText|shapesFromText|masksFromText|shapesFromVector|instance3d";
 
 fn create(s: &mut Session, p: &Value) -> Result<Value> {
     let op = str_p(p, "op").ok_or_else(|| bad("layer.create", format!("missing `op` ({OPS})")))?;
@@ -19,6 +22,69 @@ fn create(s: &mut Session, p: &Value) -> Result<Value> {
     let time = s.time();
     let mut created = vec![];
     let mut skipped = vec![];
+    // All the selected models in one edit: one undo (or redo) removes (or restores) every
+    // instance at once, as one command in the History panel.
+    if op == "instance3d" {
+        // After Effects' Create 3D Layer Instance (Layer ▸ Create): 3D model layers take
+        // no masks or effects, so a comp-sized solid goes at the top of the layer stack
+        // with a 3D Layer Instance effect referencing the model — a 2D copy of its render,
+        // through the comp's camera, that 2D effects can be applied to. The model is switched
+        // off, as After Effects does (back on to keep its shadow).
+        let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
+        let mut eligible = vec![];
+        for lid in &lids {
+            match comp.layer(*lid) {
+                Some(src) if src.source.is_model() => eligible.push((*lid, src.clone())),
+                Some(src) => skipped.push(format!("{}: not a 3D model layer", src.name)),
+                None => {}
+            }
+        }
+        if !eligible.is_empty() {
+            let ids = s.edit("Create 3D Layer Instance", None, |proj, st| {
+                let mut ids = vec![];
+                for (lid, src) in &eligible {
+                    let name = proj.comp(cid).ok_or(EngineError::NoComp)?.unique_layer_name(&format!("{} Instance", src.name));
+                    let folder = proj.folder_named("Solids").unwrap_or_else(|| proj.add_item("Solids", Label::Yellow, None, ItemKind::Folder));
+                    let sid = proj.add_item(
+                        &name,
+                        src.label,
+                        Some(folder),
+                        ItemKind::Solid(Solid { color: [1.0, 1.0, 1.0], width: comp.width, height: comp.height, pixel_aspect: 1.0 }),
+                    );
+                    let mut l = build::layer(proj, &comp, &name, LayerSource::Solid { item: sid }, (comp.width, comp.height), None);
+                    // A soloed source keeps its Solo switch with video off, and any_solo hides
+                    // the non-soloed copy: the copy takes the Solo over to stay visible.
+                    l.switches.solo = src.switches.solo;
+                    // A 3D Layer Instance effect referencing the 3D layer: the solid shows its
+                    // render (the 2D copy).
+                    let fx = effectcraft_effects::find("ec.3d.instance3d").ok_or_else(|| bad("layer.create", "the 3D Layer Instance effect is missing"))?;
+                    let mut g = effectcraft_effects::instantiate(fx, &mut Ids(&mut proj.next_id), fx.name, [comp.width as f64, comp.height as f64]);
+                    if let Some(pr) = g.get_mut("layer") {
+                        pr.value = KV::Layer(Some(lid.0));
+                    }
+                    if let Some(fxg) = l.props.sub_mut("effects") {
+                        fxg.children.push(g.into());
+                    }
+                    // The model is switched off (After Effects turns the referenced layer off);
+                    // the copies go at the top of the stack, selected.
+                    let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
+                    if let Some(m) = c.layers.iter_mut().find(|x| x.id == *lid) {
+                        m.switches.video = false;
+                    }
+                    let id = l.id;
+                    c.layers.insert(0, l);
+                    ids.push(id);
+                }
+                st.selected_layers = ids.clone();
+                Ok(ids)
+            })?;
+            created.extend(ids.iter().map(|i| i.0));
+        }
+        if created.is_empty() && !skipped.is_empty() {
+            return Err(bad("layer.create", skipped.join("; ")));
+        }
+        return Ok(json!({"layers": created, "skipped": skipped}));
+    }
     for lid in lids {
         let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
         let Some(src) = comp.layer(lid).cloned() else { continue };
@@ -198,5 +264,5 @@ fn insert_above(
 }
 
 pub fn specs() -> Vec<CommandSpec> {
-    vec![cmd!("layer.create", "Create", [], None, "{op: editableText|shapesFromText|masksFromText|shapesFromVector, layers?}", has_layers, create)]
+    vec![cmd!("layer.create", "Create", [], None, "{op: editableText|shapesFromText|masksFromText|shapesFromVector|instance3d, layers?}", has_layers, create)]
 }
diff --git a/crates/engine/src/cmd/edit.rs b/crates/engine/src/cmd/edit.rs
index bfc05933e..30c027deb 100644
--- a/crates/engine/src/cmd/edit.rs
+++ b/crates/engine/src/cmd/edit.rs
@@ -74,9 +74,9 @@ fn select_all(s: &mut Session, _: &Value) -> Result<Value> {
     Ok(json!(s.state.selected_layers.len()))
 }
 fn deselect_all(s: &mut Session, _: &Value) -> Result<Value> {
-    // A deselected layer never keeps an open text edit: commit the edit first, exactly as
-    // `text.endEdit` (an empty Type-tool layer included), so every route — menu, shortcut,
-    // script, MCP — leaves one final state.
+    // A deselected layer never keeps an open text edit: commit it first, exactly as `text.endEdit`,
+    // so every route — menu, shortcut, script, MCP — leaves one final state. An empty Type-tool
+    // layer survives, as it does in After Effects.
     super::text_edit::end_edit(s, &Value::Null)?;
     s.state.selected_layers.clear();
     s.state.selected_props.clear();
@@ -146,6 +146,11 @@ fn duplicate(s: &mut Session, p: &Value) -> Result<Value> {
         st.selected_layers = created.clone();
         Ok(created)
     })?;
+    // Duplicating selects the copies, so an open text edit on a now-deselected layer ends
+    // (#2226): typing must not keep editing an unselected layer.
+    if s.state.text_edit.as_ref().is_some_and(|e| !s.state.selected_layers.contains(&e.layer)) {
+        super::text_edit::end_edit(s, &Value::Null)?;
+    }
     Ok(json!(new.iter().map(|l| l.0).collect::<Vec<_>>()))
 }
 
diff --git a/crates/engine/src/cmd/effect.rs b/crates/engine/src/cmd/effect.rs
index 003993fde..32b0aaa2b 100644
--- a/crates/engine/src/cmd/effect.rs
+++ b/crates/engine/src/cmd/effect.rs
@@ -136,7 +136,16 @@ fn warning(s: &mut Session, p: &Value) -> Result<Value> {
     let layer = comp.layer(lid).ok_or(EngineError::NoComp)?;
     let g = layer.effects().and_then(|fx| fx.groups().find(|g| g.uid == uid)).ok_or_else(|| bad(cmd, "no such effect"))?;
     let t = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     Ok(json!({"effect": uid, "warning": effectcraft_effects::warning(g, &mut |pr| ctx.value(layer, pr))}))
 }
 
@@ -160,7 +169,16 @@ fn pick_color(s: &mut Session, p: &Value) -> Result<Value> {
     .filter(|pr| pr.ui == effectcraft_project::ParamUi::Color)
     .ok_or_else(|| bad(cmd, "not a colour parameter of this effect"))?;
     let t = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let mut r = effectcraft_render::Renderer::new(&s.project, &*s.footage, effectcraft_render::RenderOpts::default());
     r.expr = s.expr.as_deref();
     r.cache = Some(&s.layer_cache);
@@ -288,7 +306,16 @@ impl CryptoProbe {
             let comp = r.project.comp(cid).ok_or("no composition")?;
             let layer = comp.layer(lid).ok_or("no such layer")?;
             let g = layer.effects().and_then(|fx| fx.groups().nth(pos)).ok_or("no such effect")?;
-            let ctx = effectcraft_render::EvalCtx { project: r.project, comp_id: cid, comp, time, expr: r.expr, footage: None };
+            let ctx = effectcraft_render::EvalCtx {
+                project: r.project,
+                comp_id: cid,
+                comp,
+                time,
+                expr: r.expr,
+                footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
+            };
             let params = effectcraft_effects::flatten_params(g, &mut |pr| ctx.value(layer, pr));
             let want = effectcraft_effects::CRYPTO_LAYERS.get(params.e("layer") as usize).copied().unwrap_or("CryptoAsset");
             let aux = r.layer_aux(&ctx, layer).ok_or(NO_CRYPTO)?;
@@ -351,7 +378,16 @@ fn probe_key<'a>(s: &'a Session, p: &Value, cmd: &str) -> Result<(ProbeKey, Tick
     let g = fx.groups().nth(pos).ok_or_else(|| bad(cmd, "no such effect"))?;
     let prop = g.prop("selection").filter(|_| g.match_id == "ec.3d.cryptomatte").ok_or_else(|| bad(cmd, "not a Cryptomatte effect"))?;
     let time = super::time_p(s, p, Some(comp));
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let frame = probe_frame(&ctx, layer, pos);
     let o = s.render_opts(Default::default());
     let prefs = (o.nested_switches, o.draft_shadows);
@@ -503,7 +539,16 @@ fn crypto_hit(s: &Session, p: &Value, cmd: &str) -> Result<Hit> {
     let Some(hash) = b.aux.index_at(ax, ay).and_then(|i| b.aux.crypto_id_at(&b.layer, i)) else { return Ok(Hit::Nothing) };
     let (cid, lid, ..) = key.at;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time, expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time,
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let selection = effectcraft_effects::flatten_params(g, &mut |pr| ctx.value(layer, pr)).s("selection").to_string();
     let driven = prop.expr.as_ref().is_some_and(|e| e.enabled);
     let (aux, layer_name) = (b.aux.clone(), b.layer.clone());
diff --git a/crates/engine/src/cmd/expr_tools.rs b/crates/engine/src/cmd/expr_tools.rs
index fae74a5b5..cb39077af 100644
--- a/crates/engine/src/cmd/expr_tools.rs
+++ b/crates/engine/src/cmd/expr_tools.rs
@@ -163,6 +163,8 @@ pub fn language_menu() -> Vec<(&'static str, Vec<(&'static str, &'static str)>)>
                 ("easeIn(t, tMin, tMax, value1, value2)", "easeIn(t, tMin, tMax, value1, value2)"),
                 ("easeOut(t, value1, value2)", "easeOut(t, value1, value2)"),
                 ("easeOut(t, tMin, tMax, value1, value2)", "easeOut(t, tMin, tMax, value1, value2)"),
+                ("bezier(t, value1, value2, [x1, y1, x2, y2])", "bezier(t, value1, value2, [x1, y1, x2, y2])"),
+                ("bezier(t, tMin, tMax, value1, value2, [x1, y1, x2, y2])", "bezier(t, tMin, tMax, value1, value2, [x1, y1, x2, y2])"),
             ],
         ),
         (
diff --git a/crates/engine/src/cmd/file.rs b/crates/engine/src/cmd/file.rs
index 194845803..beb161a53 100644
--- a/crates/engine/src/cmd/file.rs
+++ b/crates/engine/src/cmd/file.rs
@@ -87,7 +87,8 @@ pub(crate) fn open(s: &mut Session, p: &Value) -> Result<Value> {
 /// project opened from an XML copy saves as XML again). Fails, writing nothing, when the project
 /// wouldn't read back.
 pub(crate) fn file_text(s: &Session, path: &str) -> Result<String> {
-    let json = s.project.to_file_json_with_view(&s.saved_view())?;
+    let compact = s.prefs.project.compact_project_files && !crate::xml_project::is_xml_path(path);
+    let json = s.project.to_file_json_with_view(&s.saved_view(), compact)?;
     if crate::xml_project::is_xml_path(path) { crate::xml_project::to_xml(&json).map_err(EngineError::Other) } else { Ok(json) }
 }
 
diff --git a/crates/engine/src/cmd/file_more.rs b/crates/engine/src/cmd/file_more.rs
index 1e57d4b5c..59a824208 100644
--- a/crates/engine/src/cmd/file_more.rs
+++ b/crates/engine/src/cmd/file_more.rs
@@ -878,10 +878,34 @@ fn replace_footage(s: &mut Session, p: &Value) -> Result<Value> {
     let path = str_p(p, "path").ok_or_else(|| bad("file.replaceFootage", "missing `path`"))?.to_string();
     let item = *items_p(s, p).first().ok_or_else(|| bad("file.replaceFootage", "select footage"))?;
     let importer = s.importer.clone().ok_or_else(|| EngineError::Other("media import is not available in this build".into()))?;
-    // A numbered still brings its image sequence, as on import (`sequence: false` for one frame).
-    let opts = SequenceOptions::from_params(p);
+    // Replacing a still keeps it a still; replacing a sequence keeps bringing the new file's run.
+    // `sequence`/`alphabetical` override that (#2073).
+    let previous = match s.project.item(item).map(|it| &it.kind) {
+        Some(ItemKind::Footage(f)) if f.kind == FootageKind::Sequence => (true, true, f.alphabetical),
+        _ => (false, false, false),
+    };
+    // Only `sequence` decides whether the item keeps its kind; `alphabetical` is a sequence
+    // modifier, not a request to make one.
+    let inherited = b_p(p, "sequence").is_none();
+    let mut opts = SequenceOptions::from_params(p);
+    if inherited {
+        (opts.sequence, opts.folders) = (previous.0, previous.1);
+        if previous.0 && b_p(p, "alphabetical").is_none() {
+            opts.alphabetical = previous.2;
+        }
+    }
     let src = crate::sequence::source_of(s.services.as_ref(), &path, opts);
-    let f = crate::sequence::probe(importer.as_ref(), &src, s.sequence_rate()).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
+    let mut f = crate::sequence::probe(importer.as_ref(), &src, s.sequence_rate()).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
+    // A single-file source comes back as a still; an inherited sequence kind keeps it a
+    // one-frame sequence, so a later default replacement still brings numbered runs (#2073).
+    if inherited && previous.0 && matches!(src, crate::sequence::Source::File(_)) && f.kind == FootageKind::Still {
+        f.kind = FootageKind::Sequence;
+        f.sequence = vec![f.path.clone()];
+        f.alphabetical = opts.alphabetical;
+        f.frame_rate = s.sequence_rate();
+        f.native_rate = None;
+        f.sync_sequence_duration();
+    }
     let name = src.name();
     // Replacing a missing file relinks the other missing files that moved with it (as After Effects
     // does when you locate one).
@@ -1093,7 +1117,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "File...",
             ["File", "Replace Footage"],
             Some("Cmd+H"),
-            "{path, item?, sequence?: bool (default true: a numbered still brings its image sequence), alphabetical?: bool}",
+            "{path, item?, sequence?: bool (a numbered still brings its image sequence; default: the item keeps its kind, so a still stays a still and a sequence stays a sequence), alphabetical?: bool}",
             has_footage_selection,
             replace_footage
         ),
diff --git a/crates/engine/src/cmd/focus.rs b/crates/engine/src/cmd/focus.rs
index 013672a38..356ce1a07 100644
--- a/crates/engine/src/cmd/focus.rs
+++ b/crates/engine/src/cmd/focus.rs
@@ -78,6 +78,12 @@ fn set_to_layer(s: &mut Session, p: &Value) -> Result<Value> {
     let c = "camera.setFocusToLayer";
     let (cid, cam, target) = refs(s, p, c, true)?;
     let d = focus_depth(s, cid, cam, target.ok_or_else(|| bad(c, "no layer"))?).ok_or_else(|| bad(c, "can't evaluate the layers"))?;
+    // Only a finite depth can be stored: JSON has no infinity or NaN, so the project could no
+    // longer be saved. Extreme but finite positions can still produce one, and `d <= 0.0` is
+    // false for NaN.
+    if !d.is_finite() {
+        return Err(bad(c, "can't measure the distance to the layer (the camera or layer position is out of range)"));
+    }
     if d <= 0.0 {
         return Err(bad(c, "the layer is behind the camera"));
     }
diff --git a/crates/engine/src/cmd/layer.rs b/crates/engine/src/cmd/layer.rs
index f6d2feb04..26c4b4c8c 100644
--- a/crates/engine/src/cmd/layer.rs
+++ b/crates/engine/src/cmd/layer.rs
@@ -48,7 +48,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Text",
             ["Layer", "New"],
             Some("Cmd+Alt+Shift+T"),
-            "{text?, name? (layer name; default the text), position? [x,y], box? [x,y,w,h] (paragraph text, comp space), vertical?, edit? (start editing), font?, style?, size?, fill?, stroke?, applyFill?, applyStroke?, strokeWidth?, tracking?, leading?, baselineShift?, hScale?, vScale?, tsume?, fauxBold?, fauxItalic?, allCaps?, smallCaps?, baseline?, superscript?, subscript?, kerning?, ligatures?, justify?, indentLeft?, indentRight?, indentFirst?, spaceBefore?, spaceAfter?, direction?, composer?, hangingPunctuation?, strokeOverFill?} (attributes as layer.setText)",
+            "{text?, name? (layer name; default the text), position? [x,y], box? [x,y,w,h] (paragraph text, comp space), vertical?, edit? (start editing), font?, style?, size?, fill?, stroke?, applyFill?, applyStroke?, strokeWidth?, tracking?, leading?, baselineShift?, hScale?, vScale?, tsume?, fauxBold?, fauxItalic?, allCaps?, smallCaps?, baseline?, superscript?, subscript?, kerning?, ligatures?, justify?, indentLeft?, indentRight?, indentFirst?, spaceBefore?, spaceAfter?, direction?, composer?, hangingPunctuation?, strokeOverFill?, lineJoin?} (attributes as layer.setText)",
             has_comp,
             new_text
         ),
@@ -121,7 +121,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Track Matte",
             [],
             None,
-            "{layer?, matte: layer|null, kind?: alpha|alphaInverted|luma|lumaInverted}",
+            "{layers? | layer?, matte: layer|null, kind?: alpha|alphaInverted|luma|lumaInverted|preserve}",
             has_layers,
             track_matte
         ),
@@ -192,7 +192,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Edit Text",
             [],
             None,
-            "{layer?, range?: [start, end] (characters; default all), text?, font?, style?, size?, fill?, stroke?, applyFill?, applyStroke?, strokeWidth?, tracking?, leading?: px|\"auto\", baselineShift? px, hScale? %, vScale? %, tsume? %, fauxBold?, fauxItalic?, allCaps?, smallCaps?, baseline?: normal|superscript|subscript, superscript?, subscript?, kerning?: metrics|optical|number, ligatures?, discretionaryLigatures? (OpenType), contextualAlternates?, stylisticAlternates?, stylisticSets?: [1–20], ss01?, ss02?, ss03?, ss04?, ss05?, ss06?, ss07?, ss08?, ss09?, ss10?, ss11?, ss12?, ss13?, ss14?, ss15?, ss16?, ss17?, ss18?, ss19?, ss20?, swash?, titling?, ordinals?, fractions?, allSmallCaps?, figureStyle?: default|lining|oldStyle, figureWidth?: default|proportional|tabular, figures?, variations?: {tag: value} (variable font axes; null resets), justify?: left|center|right|justifyLeft|justifyCenter|justifyRight|justifyAll, indentLeft?, indentRight?, indentFirst?, spaceBefore?, spaceAfter?, direction?: ltr|rtl, composer?: everyLine|singleLine, hangingPunctuation?, strokeOverFill?, box?: [x,y,w,h]|null (layer space), vertical?}",
+            "{layer?, range?: [start, end] (characters; default all), text?, font?, style?, size?, fill?, stroke?, applyFill?, applyStroke?, strokeWidth?, tracking?, leading?: px|\"auto\", baselineShift? px, hScale? %, vScale? %, tsume? %, fauxBold?, fauxItalic?, allCaps?, smallCaps?, baseline?: normal|superscript|subscript, superscript?, subscript?, kerning?: metrics|optical|number, ligatures?, discretionaryLigatures? (OpenType), contextualAlternates?, stylisticAlternates?, stylisticSets?: [1–20], ss01?, ss02?, ss03?, ss04?, ss05?, ss06?, ss07?, ss08?, ss09?, ss10?, ss11?, ss12?, ss13?, ss14?, ss15?, ss16?, ss17?, ss18?, ss19?, ss20?, swash?, titling?, ordinals?, fractions?, allSmallCaps?, figureStyle?: default|lining|oldStyle, figureWidth?: default|proportional|tabular, figures?, variations?: {tag: value} (variable font axes; null resets), justify?: left|center|right|justifyLeft|justifyCenter|justifyRight|justifyAll, indentLeft?, indentRight?, indentFirst?, spaceBefore?, spaceAfter?, direction?: ltr|rtl, composer?: everyLine|singleLine, hangingPunctuation?, strokeOverFill?, lineJoin?: miter|round|bevel, box?: [x,y,w,h]|null (layer space), vertical?}",
             has_layers,
             set_text
         ),
diff --git a/crates/engine/src/cmd/layer/create.rs b/crates/engine/src/cmd/layer/create.rs
index 7962c2485..ccc4810a9 100644
--- a/crates/engine/src/cmd/layer/create.rs
+++ b/crates/engine/src/cmd/layer/create.rs
@@ -161,7 +161,7 @@ pub(super) fn text_range_p(p: &Value) -> Option<std::ops::Range<usize>> {
 /// It is left justified unless `justify` is given. The layer is named by `name`, else the first 40
 /// characters of the first text line, else "Text". `edit: true` also opens a new editing
 /// session with anchor `0` and the caret after the text, selecting all initial text so the next
-/// insertion replaces it. The session has `created: true`, so leaving it empty removes the layer.
+/// insertion replaces it. The session has `created: true`; leaving it empty keeps the layer, as After Effects does.
 pub(super) fn new_text(s: &mut Session, p: &Value) -> Result<Value> {
     let cid = comp_id(s, p)?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
diff --git a/crates/engine/src/cmd/layer/parent.rs b/crates/engine/src/cmd/layer/parent.rs
index fbaec14e4..a6f49abf8 100644
--- a/crates/engine/src/cmd/layer/parent.rs
+++ b/crates/engine/src/cmd/layer/parent.rs
@@ -1,4 +1,4 @@
-use super::{Comp, EngineError, ItemId, KV, Layer, LayerId, PropGroup, Result, Session, Tick, Value, b_p, bad, layers_p, resolve_layer};
+use super::{Comp, EngineError, ItemId, KV, Layer, LayerId, PropGroup, Result, Session, Tick, Value, b_p, bad, layers_p, resolve_layer, unlocked};
 
 /// Re-express a layer in its new parent space without moving its anchor.
 pub(crate) struct ParentFix {
@@ -9,10 +9,20 @@ pub(crate) struct ParentFix {
     rotation: f64,
     /// Multiply Scale.
     scale: [f64; 2],
-    /// 3D AV layers retain their world-space anchor, including Z.
+    /// 3D AV layers retain their world-space anchor, including Z. Cameras and lights also
+    /// re-express their Point of Interest.
     position_3d: Option<effectcraft_geom::Mat4>,
-    /// A uniform relative parent transform can preserve static Orientation and Scale.
-    pose_3d: Option<([f64; 3], f64)>,
+    /// A uniform relative parent transform re-expresses static Orientation and Scale.
+    pose_3d: Option<Pose3d>,
+}
+
+/// A uniform relative parent transform, as it applies to a 3D layer's Orientation and Scale.
+#[derive(Clone, Copy)]
+struct Pose3d {
+    /// Rotation that Orientation is re-expressed under: `Orientation' = correction * Orientation`.
+    correction: effectcraft_geom::Mat4,
+    /// Uniform scale factor, multiplied into Scale (negative for a mirrored parent).
+    factor: f64,
 }
 
 impl ParentFix {
@@ -22,7 +32,7 @@ impl ParentFix {
         if let Some(m) = self.position_3d {
             // Spatial Position speed measures distance along its path. Its parent-space
             // unit changes even when the child's Orientation cannot be re-expressed.
-            let position_speed = uniform_parent_pose(m, [0.0; 3]).map(|(_, factor)| factor.abs());
+            let position_speed = uniform_rotation(m).map(|(_, factor)| factor.abs());
             let map_position = |v: &KV| {
                 let q = m.apply(effectcraft_geom::Vec3::from(v.as_vec3()));
                 KV::Vec3([q.x, q.y, q.z])
@@ -44,7 +54,8 @@ impl ParentFix {
                     }
                 }
             }
-            if let Some(pr) = tr.get_mut("position") {
+            // Position and a camera's or light's Point of Interest are both points in the parent's space.
+            let map_point = |pr: &mut effectcraft_project::Property| {
                 pr.value = map_position(&pr.value);
                 for key in &mut pr.keys {
                     key.value = map_position(&key.value);
@@ -64,34 +75,19 @@ impl ParentFix {
                         }
                     }
                 }
+            };
+            if let Some(pr) = tr.get_mut("position") {
+                map_point(pr);
             }
-            // Cameras and lights aim with Point of Interest: move it by the same parent-space
-            // change, so a two-node rig keeps its world frame (#1010, #1020).
             if let Some(pr) = tr.get_mut("poi") {
-                pr.value = map_position(&pr.value);
-                for key in &mut pr.keys {
-                    key.value = map_position(&key.value);
-                    for tangent in [&mut key.spatial_in, &mut key.spatial_out] {
-                        let v = m.apply_vec(effectcraft_geom::Vec3::from(*tangent));
-                        *tangent = [v.x, v.y, v.z];
-                    }
-                }
-                if let Some(factor) = position_speed
-                    .filter(|_| pr.spatial)
-                    .filter(|factor| pr.keys.iter().flat_map(|key| key.in_ease.iter().chain(&key.out_ease)).all(|ease| (ease.speed * *factor).is_finite()))
-                {
-                    for key in &mut pr.keys {
-                        for ease in key.in_ease.iter_mut().chain(&mut key.out_ease) {
-                            ease.speed *= factor;
-                        }
-                    }
-                }
+                map_point(pr);
             }
-            if let Some((orientation, factor)) = self.pose_3d {
+            if let Some(pose) = self.pose_3d {
                 if let Some(pr) = tr.get_mut("orientation") {
-                    pr.value = KV::Vec3(orientation);
+                    reexpress_orientation(pose.correction, pr);
                 }
                 if let Some(pr) = tr.get_mut("scale") {
+                    let factor = pose.factor;
                     let scaled = |value: &KV| KV::Vec3(value.as_vec3().map(|v| v * factor));
                     pr.value = scaled(&pr.value);
                     for key in &mut pr.keys {
@@ -154,13 +150,10 @@ impl ParentFix {
     }
 }
 
-/// A uniform factor commutes with authored axis Rotation and Scale; prepend its orthogonal
-/// rotation to static Orientation using the existing Rz * Ry * Rx order.
-fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Option<([f64; 3], f64)> {
-    use effectcraft_geom::{Mat4, Vec3, vec3};
-    if !orientation.iter().all(|v| v.is_finite()) {
-        return None;
-    }
+/// The rotation and signed scale factor of a uniform parent transform's linear part (negative for a
+/// mirrored parent). `None` for a non-uniform or degenerate transform.
+fn uniform_rotation(m: effectcraft_geom::Mat4) -> Option<(effectcraft_geom::Mat4, f64)> {
+    use effectcraft_geom::{Mat4, vec3};
     let a = m.0;
     let columns = [vec3(a[0][0], a[1][0], a[2][0]), vec3(a[0][1], a[1][1], a[2][1]), vec3(a[0][2], a[1][2], a[2][2])];
     let magnitude = columns[0].x.hypot(columns[0].y).hypot(columns[0].z);
@@ -179,15 +172,188 @@ fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Opti
             rotation.0[row][col] = a[row][col] / factor;
         }
     }
-    if (0..3).all(|row| (0..3).all(|col| (rotation.0[row][col] - if row == col { 1.0 } else { 0.0 }).abs() < 1e-12)) {
-        return Some((orientation, factor));
-    }
-    let r = (rotation * Mat4::orientation(Vec3::from(orientation))).0;
+    Some((rotation, factor))
+}
+
+/// The turn (degrees) of a rotation about Z alone, or `None` for any other rotation.
+fn z_only_turn(correction: effectcraft_geom::Mat4) -> Option<f64> {
+    let m = correction.0;
+    let about_z = [m[0][2], m[1][2], m[2][0], m[2][1]].iter().all(|v| v.abs() < 1e-9) && (m[2][2] - 1.0).abs() < 1e-9;
+    about_z.then(|| m[1][0].atan2(m[0][0]).to_degrees())
+}
+
+/// ZYX Euler angles in degrees of a row-major rotation (`Rz * Ry * Rx`), safe at gimbal lock.
+fn euler_zyx(r: [[f64; 4]; 4]) -> [f64; 3] {
     // atan2 rather than asin: near ±90 degrees asin loses precision, while cos(y) stays exact.
     let cy = r[0][0].hypot(r[1][0]);
     let y = (-r[2][0]).atan2(cy);
     let (x, z) = if cy > 1e-9 { (r[2][1].atan2(r[2][2]), r[1][0].atan2(r[0][0])) } else { ((-r[1][2]).atan2(r[1][1]), 0.0) };
-    Some(([x.to_degrees(), y.to_degrees(), z.to_degrees()], factor))
+    [x.to_degrees(), y.to_degrees(), z.to_degrees()]
+}
+
+/// The equivalent ZYX Euler triple nearest `reference`: each axis moved by whole turns, or the
+/// `(x + 180, 180 - y, z + 180)` form when that is nearer.
+fn nearest_euler(euler: [f64; 3], reference: [f64; 3]) -> [f64; 3] {
+    let near = |v: [f64; 3]| -> [f64; 3] { std::array::from_fn(|i| v[i] + ((reference[i] - v[i]) / 360.0).round() * 360.0) };
+    let natural = near(euler);
+    let flipped = near([euler[0] + 180.0, 180.0 - euler[1], euler[2] + 180.0]);
+    let distance = |v: [f64; 3]| v.iter().zip(reference.iter()).map(|(a, b)| (a - b).powi(2)).sum::<f64>();
+    if distance(flipped) < distance(natural) { flipped } else { natural }
+}
+
+/// The Euler Orientation of `correction * Orientation(o)`, in the form nearest `reference`.
+fn reexpress_euler(correction: effectcraft_geom::Mat4, o: [f64; 3], reference: [f64; 3]) -> [f64; 3] {
+    let world = correction * effectcraft_geom::Mat4::orientation(effectcraft_geom::Vec3::from(o));
+    nearest_euler(euler_zyx(world.0), reference)
+}
+
+/// Largest angle (degrees) a baked Orientation may drift from the exact rotation between its keys.
+const BAKE_TOLERANCE_DEGREES: f64 = 0.05;
+/// How many times a segment may be halved while baking, and the most keys a property may end up with.
+const BAKE_MAX_DEPTH: u32 = 10;
+const BAKE_MAX_KEYS: usize = 4096;
+
+/// The angle (degrees) between two rotations.
+fn rotation_angle(a: effectcraft_geom::Mat4, b: effectcraft_geom::Mat4) -> f64 {
+    let trace: f64 = (0..3).flat_map(|i| (0..3).map(move |j| (i, j))).map(|(i, j)| a.0[i][j] * b.0[i][j]).sum();
+    ((trace - 1.0) / 2.0).clamp(-1.0, 1.0).acos().to_degrees()
+}
+
+/// Adds keys between `(ta, ea)` and `(tb, eb)` (already converted) wherever the straight Euler blend
+/// between them drifts from `correction * Orientation(authored)` by more than the tolerance. `out`
+/// never grows past `budget` keys: what the whole property may still add, not what one segment may.
+fn bake_between(
+    correction: effectcraft_geom::Mat4,
+    authored: &effectcraft_project::Property,
+    (ta, ea): (Tick, [f64; 3]),
+    (tb, eb): (Tick, [f64; 3]),
+    depth: u32,
+    budget: usize,
+    out: &mut Vec<effectcraft_keyframe::Keyframe>,
+) {
+    use effectcraft_geom::{Mat4, Vec3};
+    if depth == 0 || tb.0 - ta.0 < 2 || out.len() >= budget {
+        return;
+    }
+    let tm = Tick(ta.0 + (tb.0 - ta.0) / 2);
+    let blend = [(ea[0] + eb[0]) / 2.0, (ea[1] + eb[1]) / 2.0, (ea[2] + eb[2]) / 2.0];
+    let exact = correction * Mat4::orientation(Vec3::from(authored.value_at(tm).as_vec3()));
+    // Symmetric easing crosses the straight blend at its midpoint. Check both sides too before
+    // accepting a segment whose original easing will be replaced with a linear blend.
+    let quarter = (tb.0 - ta.0) / 4;
+    if [Tick(ta.0 + quarter), tm, Tick(tb.0 - quarter)].into_iter().all(|t| {
+        let u = (t.0 - ta.0) as f64 / (tb.0 - ta.0) as f64;
+        let linear = std::array::from_fn(|i| ea[i] + (eb[i] - ea[i]) * u);
+        let target = correction * Mat4::orientation(Vec3::from(authored.value_at(t).as_vec3()));
+        rotation_angle(Mat4::orientation(Vec3::from(linear)), target) <= BAKE_TOLERANCE_DEGREES
+    }) {
+        return;
+    }
+    let em = nearest_euler(euler_zyx(exact.0), blend);
+    bake_between(correction, authored, (ta, ea), (tm, em), depth - 1, budget, out);
+    if out.len() >= budget {
+        return;
+    }
+    out.push(effectcraft_keyframe::Keyframe::new(tm, KV::Vec3(em)));
+    bake_between(correction, authored, (tm, em), (tb, eb), depth - 1, budget, out);
+}
+
+/// Re-expresses Orientation as `correction * Orientation`. A Z-only correction shifts Z exactly in the
+/// value and every key. For any other correction a static value is converted directly; keys are
+/// converted, and keys are added between them wherever the Euler blend between two keys would drift
+/// from the exact rotation (the segments become linear, with the original easing baked in).
+fn reexpress_orientation(correction: effectcraft_geom::Mat4, pr: &mut effectcraft_project::Property) {
+    if let Some(turn) = z_only_turn(correction) {
+        // No turn (an identity correction) leaves every authored value as it is.
+        if turn.abs() <= 1e-12 {
+            return;
+        }
+        let shift = |value: &KV| {
+            let [x, y, z] = value.as_vec3();
+            KV::Vec3([x, y, z + turn])
+        };
+        pr.value = shift(&pr.value);
+        for key in &mut pr.keys {
+            key.value = shift(&key.value);
+        }
+        return;
+    }
+    let value = pr.value.as_vec3();
+    pr.value = KV::Vec3(reexpress_euler(correction, value, value));
+    if pr.keys.is_empty() {
+        return;
+    }
+    let authored = pr.clone();
+    // Each key keeps the authored change from the previous key on top of its converted value.
+    let mut converted: Vec<[f64; 3]> = vec![];
+    let mut prev: Option<([f64; 3], [f64; 3])> = None;
+    for key in &authored.keys {
+        let o = key.value.as_vec3();
+        let reference = match prev {
+            Some((before, after)) => [after[0] + o[0] - before[0], after[1] + o[1] - before[1], after[2] + o[2] - before[2]],
+            None => o,
+        };
+        let n = reexpress_euler(correction, o, reference);
+        converted.push(n);
+        prev = Some((o, n));
+    }
+    use effectcraft_keyframe::Interp;
+    let mut keys: Vec<effectcraft_keyframe::Keyframe> = vec![];
+    let mut after_baked_segment = false;
+    for (i, key) in authored.keys.iter().enumerate() {
+        let mut k = key.clone();
+        k.value = KV::Vec3(converted[i]);
+        if after_baked_segment {
+            k.in_interp = Interp::Linear;
+            k.in_ease.clear();
+            k.auto_bezier = false;
+            k.continuous = false;
+        }
+        after_baked_segment = false;
+        let segment = authored.keys.get(i + 1).filter(|_| key.out_interp != Interp::Hold);
+        let mut between = vec![];
+        if let Some(next) = segment {
+            // What the whole property may still add: the keys it will have already (the ones written
+            // and the authored ones still to come) count against the cap.
+            let budget = BAKE_MAX_KEYS.saturating_sub(keys.len() + authored.keys.len() - i);
+            bake_between(correction, &authored, (key.time, converted[i]), (next.time, converted[i + 1]), BAKE_MAX_DEPTH, budget, &mut between);
+            // With the cap reached the segment can't be checked or subdivided: it keeps its authored easing between
+            // the converted keys, rather than becoming a straight blend that was never checked against the original.
+            if between.len() >= budget {
+                between.clear();
+            // An eased segment, or one that gained keys, becomes a run of straight blends.
+            } else if !between.is_empty() || key.out_interp != Interp::Linear || next.in_interp != Interp::Linear {
+                k.out_interp = Interp::Linear;
+                k.out_ease.clear();
+                k.auto_bezier = false;
+                k.continuous = false;
+                after_baked_segment = true;
+            }
+        }
+        keys.push(k);
+        keys.extend(between);
+    }
+    pr.keys = keys;
+}
+
+/// Correction for a two-node rig's Orientation: after a uniform parent change its aim is
+/// `rotation * aim`, so the roll is re-expressed against that aim. `None` for a degenerate aim.
+fn aim_correction(rotation: effectcraft_geom::Mat4, aim: [f64; 3]) -> Option<effectcraft_geom::Mat4> {
+    use effectcraft_geom::vec3;
+    use effectcraft_render::three_d::camera::basis_rotation;
+    let [x, y, z] = aim;
+    let length = (x * x + y * y + z * z).sqrt();
+    if !length.is_finite() || length <= 1e-9 {
+        return None;
+    }
+    let dir = vec3(x / length, y / length, z / length);
+    let turned = rotation.apply_vec(dir);
+    // A view along the up axis has no roll to keep, and its basis is undefined.
+    if 1.0 - dir.y * dir.y < 1e-12 || 1.0 - turned.y * turned.y < 1e-12 {
+        return None;
+    }
+    let up = vec3(0.0, 1.0, 0.0);
+    Some(basis_rotation(turned, up).transpose() * rotation * basis_rotation(dir, up))
 }
 
 /// A parent change retains 2D transforms and the world-space anchor of 3D layers (Position,
@@ -196,8 +362,16 @@ fn uniform_parent_pose(m: effectcraft_geom::Mat4, orientation: [f64; 3]) -> Opti
 /// time.
 pub(crate) fn parent_fixes(s: &Session, cid: ItemId, ids: &[LayerId], parent: Option<LayerId>) -> Vec<ParentFix> {
     let Some(comp) = s.project.comp(cid) else { return vec![] };
-    let ectx =
-        effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ectx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let space = |id: Option<LayerId>| -> effectcraft_geom::Mat3 {
         id.and_then(|i| comp.layer(i)).filter(|l| !l.is_3d()).map(|l| ectx.layer_to_comp(l).0).unwrap_or(effectcraft_geom::Mat3::IDENTITY)
     };
@@ -235,31 +409,58 @@ pub(crate) fn parent_fixes(s: &Session, cid: ItemId, ids: &[LayerId], parent: Op
         })
     };
     if let Some(inv) = space_3d(parent).inverse().filter(|m| m.0.iter().flatten().all(|v| v.is_finite())) {
-        // Cameras and lights compensate like 3D layers (Position, and Point of Interest for
-        // two-node rigs), so parenting keeps the world frame (#1010, #1020). They have no
-        // Scale, so `pose_3d` below stays `None` and Orientation is kept as authored.
         for layer in comp.layers.iter().filter(|l| ids.contains(&l.id) && l.is_3d() && l.parent != parent) {
             let m = inv * space_3d(layer.parent);
+            // A one-node camera or light has no Scale to carry a mirror, and its frame (forward and
+            // down) would come out reversed: compensate none of it, so Position and Orientation stay
+            // as authored instead of half-following the parent.
+            let rig = layer.is_camera() || layer.is_light();
+            if rig && !effectcraft_render::three_d::camera::is_two_node(layer) && uniform_rotation(m).is_some_and(|(_, factor)| factor <= 0.0) {
+                continue;
+            }
             if m.0.iter().flatten().all(|v| v.is_finite()) {
                 let pose_3d = layer.transform().and_then(|tr| {
                     let orientation = tr.get("orientation")?;
-                    let scale = tr.get("scale")?;
-                    // Animated Euler Orientation and auto-orient cannot be re-expressed by
-                    // prepending a constant Euler value. Expression-driven values stay authored.
-                    if !orientation.keys.is_empty()
-                        || orientation.expr.is_some()
-                        || scale.expr.is_some()
-                        || layer.auto_orient != effectcraft_project::AutoOrient::Off
+                    // Cameras and lights have no Scale; their Orientation is re-expressed alone.
+                    let scale = tr.get("scale");
+                    // Expression-driven values stay authored. Auto-orient replaces Orientation, except
+                    // a two-node rig, whose roll is re-expressed against its new aim.
+                    let two_node = (layer.is_camera() || layer.is_light()) && effectcraft_render::three_d::camera::is_two_node(layer);
+                    if orientation.expr.is_some()
+                        || scale.is_some_and(|scale| scale.expr.is_some())
+                        || (layer.auto_orient != effectcraft_project::AutoOrient::Off && !two_node)
                     {
                         return None;
                     }
-                    let pose = uniform_parent_pose(m, orientation.value.as_vec3())?;
-                    let factor = pose.1;
-                    let values_finite = std::iter::once(&scale.value)
-                        .chain(scale.keys.iter().map(|key| &key.value))
-                        .all(|value| value.as_vec3().iter().all(|v| (v * factor).is_finite()));
-                    let speeds_finite = scale.keys.iter().flat_map(|key| key.in_ease.iter().chain(&key.out_ease)).all(|ease| (ease.speed * factor).is_finite());
-                    (values_finite && speeds_finite).then_some(pose)
+                    let (rotation, factor) = uniform_rotation(m)?;
+                    let correction = if two_node {
+                        // A mirrored parent flips the aim, which this correction does not model.
+                        if factor <= 0.0 {
+                            return None;
+                        }
+                        let (w, h) = (comp.width as f64, comp.height as f64);
+                        let pos = ectx.v3(layer, tr, "position", [w / 2.0, h / 2.0, -1000.0]);
+                        let poi = ectx.v3(layer, tr, "poi", [w / 2.0, h / 2.0, 0.0]);
+                        aim_correction(rotation, [poi[0] - pos[0], poi[1] - pos[1], poi[2] - pos[2]])?
+                    } else {
+                        rotation
+                    };
+                    let orientation_finite = std::iter::once(&orientation.value)
+                        .chain(orientation.keys.iter().map(|key| &key.value))
+                        .all(|value| value.as_vec3().iter().all(|v| v.is_finite()));
+                    if !correction.0.iter().flatten().all(|v| v.is_finite()) || !orientation_finite {
+                        return None;
+                    }
+                    if let Some(scale) = scale {
+                        let values_finite = std::iter::once(&scale.value)
+                            .chain(scale.keys.iter().map(|key| &key.value))
+                            .all(|value| value.as_vec3().iter().all(|v| (v * factor).is_finite()));
+                        let speeds_finite = scale.keys.iter().all(|key| key.in_ease.iter().chain(&key.out_ease).all(|ease| (ease.speed * factor).is_finite()));
+                        if !values_finite || !speeds_finite {
+                            return None;
+                        }
+                    }
+                    Some(Pose3d { correction, factor })
                 });
                 fixes.push(ParentFix { layer: layer.id, m: effectcraft_geom::Mat3::IDENTITY, rotation: 0.0, scale: [1.0; 2], position_3d: Some(m), pose_3d });
             }
@@ -309,6 +510,8 @@ fn check_parent_chain(comp: &Comp, ids: &[LayerId], parent: Option<LayerId>, max
 
 pub(super) fn set_parent(s: &mut Session, p: &Value) -> Result<Value> {
     let (cid, ids) = layers_p(s, p)?;
+    // Locked layers keep their parent (several at once: the others are parented).
+    let ids = unlocked(s, cid, ids, "layer.setParent")?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
     let parent = match p.get("parent") {
         None | Some(Value::Null) => None,
diff --git a/crates/engine/src/cmd/layer/switches.rs b/crates/engine/src/cmd/layer/switches.rs
index 38689afbb..7679d34fa 100644
--- a/crates/engine/src/cmd/layer/switches.rs
+++ b/crates/engine/src/cmd/layer/switches.rs
@@ -1,6 +1,6 @@
 use super::{
     BlendMode, EngineError, FrameBlend, ItemId, KV, Layer, LayerId, MatteKind, Quality, Result, Session, TrackMatte, Value, b_p, bad, json, layer_mut, layer_p,
-    layers_p, merge_p, resolve_layer, str_p,
+    layers_p, merge_p, resolve_layer, str_p, unlocked,
 };
 
 pub(super) fn set_switch(s: &mut Session, p: &Value) -> Result<Value> {
@@ -181,33 +181,122 @@ pub(super) fn blend(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(Value::Null)
 }
 
+/// `layer.setTrackMatte`: `layers` (or `layer`, else the first selected layer; locked ones left
+/// as they are) use `matte` as their track matte (none when null), in one undo step. `kind` sets the mode; `preserve` keeps
+/// each layer's own (Alpha for a layer without a matte), so changing the matte of several layers
+/// at once keeps their modes.
 pub(super) fn track_matte(s: &mut Session, p: &Value) -> Result<Value> {
-    let (cid, lid) = layer_p(s, p, "layer.setTrackMatte")?;
+    let (cid, ids) = match p.get("layers") {
+        Some(_) => layers_p(s, p)?,
+        None => layer_p(s, p, "layer.setTrackMatte").map(|(c, l)| (c, vec![l]))?,
+    };
+    // Locked layers keep their matte (several at once: the others get it).
+    let ids = unlocked(s, cid, ids, "layer.setTrackMatte")?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
     let matte = match p.get("matte") {
         None | Some(Value::Null) => None,
         Some(v) => Some(resolve_layer(comp, v).ok_or_else(|| bad("layer.setTrackMatte", "no such matte layer"))?),
     };
-    let kind = str_p(p, "kind")
-        .map(|k| match k.to_ascii_lowercase().replace([' ', '_', '-'], "").as_str() {
+    if ids.is_empty() {
+        return Err(bad("layer.setTrackMatte", "no layers"));
+    }
+    if matte.is_some_and(|m| ids.contains(&m)) {
+        return Err(bad("layer.setTrackMatte", "a layer can't be its own matte"));
+    }
+    // None: each layer keeps its own mode.
+    let kind = match str_p(p, "kind").map(|k| k.to_ascii_lowercase().replace([' ', '_', '-'], "")) {
+        Some(k) if k == "preserve" => None,
+        Some(k) => Some(match k.as_str() {
             "alphainverted" | "alphainv" => MatteKind::AlphaInverted,
             "luma" => MatteKind::Luma,
             "lumainverted" | "lumainv" => MatteKind::LumaInverted,
             _ => MatteKind::Alpha,
-        })
-        .unwrap_or(MatteKind::Alpha);
+        }),
+        None => Some(MatteKind::Alpha),
+    };
     s.edit("Track Matte", None, |proj, _| {
         let comp = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
-        if let Some(m) = matte {
-            if m == lid {
-                return Err(bad("layer.setTrackMatte", "a layer can't be its own matte"));
-            }
-            if let Some(ml) = comp.layer_mut(m) {
-                ml.switches.video = false;
-            }
+        if let Some(ml) = matte.and_then(|m| comp.layer_mut(m)) {
+            ml.switches.video = false;
+        }
+        for lid in &ids {
+            let l = comp.layer_mut(*lid).ok_or(EngineError::NoComp)?;
+            let kind = kind.unwrap_or_else(|| l.track_matte.map(|m| m.kind).unwrap_or_default());
+            l.track_matte = matte.map(|layer| TrackMatte { layer, kind });
         }
-        comp.layer_mut(lid).ok_or(EngineError::NoComp)?.track_matte = matte.map(|layer| TrackMatte { layer, kind });
         Ok(())
     })?;
     Ok(Value::Null)
 }
+
+#[cfg(test)]
+mod track_matte_batch_tests {
+    use super::*;
+    use std::sync::Arc;
+
+    fn matte_of(s: &Session, id: u64) -> Option<(u64, MatteKind)> {
+        s.active_comp().unwrap().layer(LayerId(id)).unwrap().track_matte.map(|m| (m.layer.0, m.kind))
+    }
+
+    /// #1260: several layers take one matte layer at once, in one undo step; `kind: "preserve"`
+    /// keeps each one's mode; refused calls change nothing; one `layer` still works.
+    #[test]
+    fn several_layers_take_one_matte_and_keep_their_modes() {
+        let mut s = Session::default();
+        s.execute("comp.new", json!({"name":"Mattes","width":16,"height":16,"duration":1})).unwrap();
+        let [a, b, c, x, y] = ["A", "B", "C", "X", "Y"].map(|n| s.execute("layer.newSolid", json!({"name": n})).unwrap()["layer"].as_u64().unwrap());
+        s.execute("layer.setTrackMatte", json!({"layer": a, "matte": x, "kind": "luma"})).unwrap();
+        s.execute("layer.setTrackMatte", json!({"layer": b, "matte": x})).unwrap();
+        assert_eq!((matte_of(&s, a), matte_of(&s, b)), (Some((x, MatteKind::Luma)), Some((x, MatteKind::Alpha))), "one layer, as before");
+        let (before, undo) = (s.project.clone(), s.history.undo.len());
+        s.execute("layer.setTrackMatte", json!({"layers": [a, b, c], "matte": y, "kind": "preserve"})).unwrap();
+        assert_eq!(
+            [matte_of(&s, a), matte_of(&s, b), matte_of(&s, c)],
+            [Some((y, MatteKind::Luma)), Some((y, MatteKind::Alpha)), Some((y, MatteKind::Alpha))],
+            "each keeps its mode (Alpha without one)"
+        );
+        assert!(!s.active_comp().unwrap().layer(LayerId(y)).unwrap().switches.video, "the matte is hidden");
+        assert_eq!(s.history.undo.len(), undo + 1, "one undo step");
+        s.execute("edit.undo", json!({})).unwrap();
+        assert!(s.project.same_content(&before));
+        // Refused: a layer as its own matte, an unknown layer, no layers. Nothing changes.
+        for p in [
+            json!({"layers": [a, y], "matte": y}),
+            json!({"layers": [a, 9999], "matte": y}),
+            json!({"layers": [], "matte": y}),
+            json!({"layers": [a], "matte": 9999}),
+        ] {
+            let (project, revision) = (s.project.clone(), s.revision);
+            assert!(s.execute("layer.setTrackMatte", p.clone()).is_err(), "{p}");
+            assert!(Arc::ptr_eq(&project, &s.project) && s.revision == revision, "{p} changed nothing");
+        }
+        s.execute("layer.setTrackMatte", json!({"layers": [a, b], "matte": null})).unwrap();
+        assert_eq!((matte_of(&s, a), matte_of(&s, b)), (None, None), "both lose it");
+    }
+
+    /// Locked layers keep their parent and matte when they are among several (the others change),
+    /// and alone they are an error that changes nothing.
+    #[test]
+    fn locked_layers_keep_their_parent_and_matte() {
+        let mut s = Session::default();
+        s.execute("comp.new", json!({"name":"Locks","width":16,"height":16,"duration":1})).unwrap();
+        let [a, b, p, m] = ["A", "B", "P", "M"].map(|n| s.execute("layer.newSolid", json!({"name": n})).unwrap()["layer"].as_u64().unwrap());
+        s.execute("layer.setSwitch", json!({"layers": [b], "switch": "lock", "value": true})).unwrap();
+        let layer = |s: &Session, id: u64| s.active_comp().unwrap().layer(LayerId(id)).unwrap().clone();
+        s.execute("layer.setParent", json!({"layers": [a, b], "parent": p})).unwrap();
+        s.execute("layer.setTrackMatte", json!({"layers": [a, b], "matte": m, "kind": "preserve"})).unwrap();
+        s.execute("layer.trackMatte", json!({"layers": [a, b], "op": "luma"})).unwrap();
+        assert_eq!((layer(&s, a).parent, matte_of(&s, a)), (Some(LayerId(p)), Some((m, MatteKind::Luma))));
+        assert_eq!((layer(&s, b).parent, matte_of(&s, b)), (None, None), "the locked layer is left as it was");
+        for (cmd, p) in [
+            ("layer.setParent", json!({"layers": [b], "parent": p})),
+            ("layer.setTrackMatte", json!({"layers": [b], "matte": m})),
+            ("layer.trackMatte", json!({"layers": [b], "op": "alpha"})),
+        ] {
+            let (project, revision) = (s.project.clone(), s.revision);
+            let err = s.execute(cmd, p).unwrap_err();
+            assert!(err.to_string().contains("is locked"), "{cmd}: {err}");
+            assert!(Arc::ptr_eq(&project, &s.project) && s.revision == revision, "{cmd} changed nothing");
+        }
+    }
+}
diff --git a/crates/engine/src/cmd/layer/timing.rs b/crates/engine/src/cmd/layer/timing.rs
index 711eefee2..78f6cdc3c 100644
--- a/crates/engine/src/cmd/layer/timing.rs
+++ b/crates/engine/src/cmd/layer/timing.rs
@@ -42,7 +42,9 @@ pub(super) fn timing(s: &mut Session, p: &Value) -> Result<Value> {
                     shift(l, d);
                 }
                 "trimInToTime" => l.in_point = t.min(l.out_point - fd),
-                "trimOutToTime" => l.out_point = t.max(l.in_point + fd),
+                // Alt+]: the Out edge lands one frame after the playhead, so its frame stays the
+                // layer's last visible one (as in After Effects), never before the In point.
+                "trimOutToTime" => l.out_point = t.max(l.in_point) + fd,
                 _ => {
                     if let Some(d) = delta {
                         shift(l, d);
diff --git a/crates/engine/src/cmd/layer/transform.rs b/crates/engine/src/cmd/layer/transform.rs
index 8b75dcbc8..eb0f610f9 100644
--- a/crates/engine/src/cmd/layer/transform.rs
+++ b/crates/engine/src/cmd/layer/transform.rs
@@ -74,14 +74,39 @@ pub(super) fn transform_op(s: &mut Session, p: &Value) -> Result<Value> {
     let op = str_p(p, "op").unwrap_or("reset").to_string();
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?.clone();
     let t = s.time();
-    let sizes: Vec<(LayerId, (u32, u32))> =
-        comp.layers.iter().filter(|l| ids.contains(&l.id)).map(|l| (l.id, effectcraft_render::source_size(&s.project, l))).collect();
+    // A shape or text layer has no source item, so source_size is (0, 0): the fit ops size it by
+    // its painted bounds at the current time instead, and anchor at the bounds' centre — content
+    // bounds live in layer space, where a shape is centred on the origin and text sits above its
+    // baseline, so (w/2, h/2) would push it off-centre (#2198). Reset and the other ops keep the
+    // source size.
+    let ectx = effectcraft_render::EvalCtx {
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        ..effectcraft_render::EvalCtx::new(&s.project, cid, &comp, t)
+    };
+    let fitting = matches!(op.as_str(), "fit" | "fitWidth" | "fitHeight");
+    let sizes: Vec<(LayerId, [f64; 2], [f64; 2])> = comp
+        .layers
+        .iter()
+        .filter(|l| ids.contains(&l.id))
+        .map(|l| {
+            let (w, h) = effectcraft_render::source_size(&s.project, l);
+            if fitting && (w == 0 || h == 0) {
+                match effectcraft_render::content_bounds(&ectx, l).filter(|b| b.iter().all(|v| v.is_finite()) && b[2] > b[0] && b[3] > b[1]) {
+                    Some(b) => (l.id, [b[2] - b[0], b[3] - b[1]], [(b[0] + b[2]) / 2.0, (b[1] + b[3]) / 2.0]),
+                    None => (l.id, [0.0; 2], [0.0; 2]),
+                }
+            } else {
+                (l.id, [w as f64, h as f64], [w as f64 / 2.0, h as f64 / 2.0])
+            }
+        })
+        .collect();
     s.edit("Transform", None, |proj, _| {
-        for (lid, (w, h)) in &sizes {
+        for (lid, size, anchor) in &sizes {
             let l = layer_mut(proj, cid, *lid)?;
             let lt = l.layer_time(t);
             let (cw, ch) = (comp.width as f64, comp.height as f64);
-            let (w, h) = (*w as f64, *h as f64);
+            let (w, h) = (size[0], size[1]);
             let Some(tr) = l.transform_mut() else { continue };
             let set = |tr: &mut PropGroup, m: &str, v: KV| {
                 if let Some(pr) = tr.get_mut(m) {
@@ -105,11 +130,15 @@ pub(super) fn transform_op(s: &mut Session, p: &Value) -> Result<Value> {
                         "fitHeight" => (ch / h, ch / h),
                         _ => (cw / w, ch / h),
                     };
+                    // A tiny shape's bounds can overflow the scale; refuse rather than write infinity.
+                    if !(sx * 100.0).is_finite() || !(sy * 100.0).is_finite() {
+                        return Err(EngineError::Other(format!("layer {} is too small to fit to the composition", lid.0)));
+                    }
                     let z = |m: &str, d: f64| tr.get(m).map(|p| p.value_at(lt).as_vec3()[2]).unwrap_or(d);
                     let (sz, az) = (z("scale", 100.0), z("anchor", 0.0));
                     set(tr, "scale", KV::Vec3([sx * 100.0, sy * 100.0, sz]));
                     update_position(tr, lt, |p| [cw / 2.0, ch / 2.0, p[2]]);
-                    set(tr, "anchor", KV::Vec3([w / 2.0, h / 2.0, az]));
+                    set(tr, "anchor", KV::Vec3([anchor[0], anchor[1], az]));
                 }
                 "flipH" | "flipV" => {
                     let cur = tr.get("scale").map(|p| p.value_at(lt).as_vec3()).unwrap_or([100.0; 3]);
diff --git a/crates/engine/src/cmd/layer_menu.rs b/crates/engine/src/cmd/layer_menu.rs
index 33d17bb4f..ec8a1dfc3 100644
--- a/crates/engine/src/cmd/layer_menu.rs
+++ b/crates/engine/src/cmd/layer_menu.rs
@@ -609,6 +609,7 @@ fn delete_all_markers(s: &mut Session, p: &Value) -> Result<Value> {
 
 fn track_matte_op(s: &mut Session, p: &Value) -> Result<Value> {
     let (cid, ids) = layers_p(s, p)?;
+    let ids = super::unlocked(s, cid, ids, "layer.trackMatte")?;
     let op = str_p(p, "op").ok_or_else(|| bad("layer.trackMatte", "missing `op`"))?.to_string();
     let kind = match op.as_str() {
         "alpha" => Some(MatteKind::Alpha),
diff --git a/crates/engine/src/cmd/layer_time.rs b/crates/engine/src/cmd/layer_time.rs
index d98bfdea7..368e280c6 100644
--- a/crates/engine/src/cmd/layer_time.rs
+++ b/crates/engine/src/cmd/layer_time.rs
@@ -185,7 +185,16 @@ fn freeze(s: &mut Session, p: &Value, last: bool) -> Result<Value> {
         return Err(bad("layer.freezeFrame", "freezing needs a footage or composition layer"));
     }
     // What each layer shows now (honouring an existing remap) — evaluated before the edit.
-    let ectx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: cti, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ectx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: cti,
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let now: Vec<(effectcraft_project::LayerId, f64)> = comp
         .layers
         .iter()
diff --git a/crates/engine/src/cmd/markers.rs b/crates/engine/src/cmd/markers.rs
index 4c979619e..3530eaa4b 100644
--- a/crates/engine/src/cmd/markers.rs
+++ b/crates/engine/src/cmd/markers.rs
@@ -296,8 +296,9 @@ fn convert(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(Value::Null)
 }
 
-/// Layer ▸ Markers ▸ Update Markers From Source: copy a precomp's composition markers onto the
-/// layer (layer time is the nested comp's time), skipping ones already there.
+/// Layer ▸ Markers ▸ Update Markers From Source: copy a precomp's composition markers, or the
+/// markers a footage file carries (a WAV's cue points), onto the layer (layer time is the source's
+/// time), skipping ones already there.
 fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
     let (cid, ids) = layers_p(s, p)?;
     let src: Vec<(LayerId, Vec<Marker>)> = {
@@ -307,13 +308,17 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
                 let l = comp.layer(*id)?;
                 match &l.source {
                     LayerSource::Comp { item } => Some((*id, s.project.comp(*item)?.markers.clone())),
+                    LayerSource::Footage { item } => match &s.project.item(*item)?.kind {
+                        effectcraft_project::ItemKind::Footage(f) => Some((*id, f.markers.clone())),
+                        _ => None,
+                    },
                     _ => None,
                 }
             })
             .collect()
     };
     if src.is_empty() {
-        return Err(bad("layer.updateMarkersFromSource", "select a precomposition layer"));
+        return Err(bad("layer.updateMarkersFromSource", "select a precomposition or footage layer"));
     }
     let n = s.edit("Update Markers From Source", None, |proj, _| {
         let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
@@ -323,8 +328,11 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
             if l.markers_locked {
                 continue;
             }
+            // One set of the times already on the layer: a file with thousands of markers must not
+            // scan the layer's list for each of them.
+            let mut times: std::collections::HashSet<_> = l.markers.iter().map(|x| x.time).collect();
             for m in ms {
-                if !l.markers.iter().any(|x| x.time == m.time) {
+                if times.insert(m.time) {
                     l.markers.push(m.clone());
                     n += 1;
                 }
@@ -339,10 +347,10 @@ fn update_from_source(s: &mut Session, p: &Value) -> Result<Value> {
 fn has_precomp_layer(s: &Session) -> std::result::Result<(), String> {
     has_layers(s)?;
     let c = s.active_comp().ok_or("no composition")?;
-    if s.state.selected_layers.iter().filter_map(|l| c.layer(*l)).any(|l| matches!(l.source, LayerSource::Comp { .. })) {
+    if s.state.selected_layers.iter().filter_map(|l| c.layer(*l)).any(|l| matches!(l.source, LayerSource::Comp { .. } | LayerSource::Footage { .. })) {
         Ok(())
     } else {
-        Err("select a precomposition layer".into())
+        Err("select a precomposition or footage layer".into())
     }
 }
 
diff --git a/crates/engine/src/cmd/path_nulls.rs b/crates/engine/src/cmd/path_nulls.rs
index bb74ee77c..93d71cd67 100644
--- a/crates/engine/src/cmd/path_nulls.rs
+++ b/crates/engine/src/cmd/path_nulls.rs
@@ -78,7 +78,16 @@ fn info(s: &Session, cid: ItemId, lid: LayerId, uid: Uid, cmd: &str) -> Result<P
     let layer = comp.layer(lid).ok_or(EngineError::NoComp)?;
     let pr = layer.props.find(uid).ok_or_else(|| bad(cmd, "no such property"))?;
     let t = s.time();
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let KV::Path(path) = ctx.value(layer, pr) else { return Err(bad(cmd, "that property is not a path")) };
     if path.vertices.is_empty() {
         return Err(bad(cmd, "the path has no vertices"));
@@ -147,8 +156,16 @@ fn pin_targets(s: &Session, p: &Value, cmd: &str) -> Result<Option<(ItemId, Vec<
     };
     let cid = pins.first().map(|x| x.0).ok_or_else(|| bad(cmd, "no puppet pins"))?;
     let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
-    let ctx =
-        effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: Some(s.footage.as_ref()),
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let mut out = vec![];
     for (_, lid, uid) in pins {
         let Some(layer) = comp.layer(lid) else { continue };
diff --git a/crates/engine/src/cmd/paths.rs b/crates/engine/src/cmd/paths.rs
index afd7aba12..7803e8fac 100644
--- a/crates/engine/src/cmd/paths.rs
+++ b/crates/engine/src/cmd/paths.rs
@@ -8,7 +8,7 @@ use effectcraft_project::{FeatherFalloff, GroupKind, ItemId, LayerId, LayerSourc
 use serde_json::{Value, json};
 
 use super::layer_menu::target_masks;
-use super::{CommandSpec, b_p, bad, f_p, has_comp, has_layers, layer_mut, layer_p, str_p};
+use super::{CommandSpec, b_p, bad, f_p, has_comp, has_layers, layer_mut, layer_p, merge_p, str_p};
 use crate::{EngineError, Result, Session, VertexRef, cmd};
 
 // ---------------------------------------------------------------- RotoBezier
@@ -308,7 +308,7 @@ fn free_transform(s: &mut Session, p: &Value) -> Result<Value> {
         let y = v[1] * scale[1];
         [x * c - y * sn, x * sn + y * c]
     };
-    let n = s.edit("Free Transform Points", None, |proj, _| {
+    let n = s.edit("Free Transform Points", merge_p(p), |proj, _| {
         let mut n = 0;
         for (lid, uid) in &targets {
             let l = layer_mut(proj, cid, *lid)?;
@@ -542,7 +542,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Free Transform Points",
             ["Layer", "Mask and Shape Path"],
             None,
-            "{layer?, mask?, scale?: % | [x%, y%], rotation?: deg, offset?: [dx, dy], anchor?: [x, y]}",
+            "{layer?, mask?, scale?: % | [x%, y%], rotation?: deg, offset?: [dx, dy], anchor?: [x, y], merge?: string}",
             has_layers,
             free_transform
         ),
diff --git a/crates/engine/src/cmd/prop.rs b/crates/engine/src/cmd/prop.rs
index 00232967e..ab2f0a1e2 100644
--- a/crates/engine/src/cmd/prop.rs
+++ b/crates/engine/src/cmd/prop.rs
@@ -1285,8 +1285,16 @@ fn convert_one_expr(s: &mut Session, cid: ItemId, lid: LayerId, uid: Uid) -> Res
     let fd = comp.frame_duration();
     let mut t = layer.in_point;
     while t < layer.out_point {
-        let ctx =
-            effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp: &comp, time: t, expr: s.expr.as_deref(), footage: Some(s.footage.as_ref()) };
+        let ctx = effectcraft_render::EvalCtx {
+            project: &s.project,
+            comp_id: cid,
+            comp: &comp,
+            time: t,
+            expr: s.expr.as_deref(),
+            footage: Some(s.footage.as_ref()),
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         keys.push(Keyframe::new(layer.layer_time(t), ctx.value(&layer, &pr)));
         t += fd;
     }
diff --git a/crates/engine/src/cmd/puppet.rs b/crates/engine/src/cmd/puppet.rs
index 320e1d415..1d080e773 100644
--- a/crates/engine/src/cmd/puppet.rs
+++ b/crates/engine/src/cmd/puppet.rs
@@ -38,7 +38,8 @@ pub fn puppet_eval(s: &Session, cid: ItemId, lid: LayerId, fx_uid: Uid, t: Tick)
     let fx = layer.effects()?;
     let index = fx.groups().position(|g| g.uid == fx_uid)?;
     let g = fx.groups().nth(index)?;
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let mut r = Renderer::new(&s.project, &*s.footage, RenderOpts::default());
     r.expr = s.expr.as_deref();
     r.cache = Some(&s.layer_cache);
diff --git a/crates/engine/src/cmd/render_queue.rs b/crates/engine/src/cmd/render_queue.rs
index 079c9bd30..00e078372 100644
--- a/crates/engine/src/cmd/render_queue.rs
+++ b/crates/engine/src/cmd/render_queue.rs
@@ -619,7 +619,7 @@ fn set_output_module(s: &mut Session, p: &Value) -> Result<Value> {
         let (w, h) = item.settings.output_size(comp);
         let mut crop_only = om.clone();
         crop_only.resize.enabled = false;
-        let (cw, ch) = crop_only.frame_size(w, h, item.settings.resolution.clamp(0.01, 4.0));
+        let (cw, ch) = crop_only.frame_size(w, h, item.settings.effective_scale(comp));
         om.resize.width = ((om.resize.height as f64 * cw as f64 / ch as f64).round() as u32).clamp(1, 30_000);
     }
     let post = match str_p(p, "postRenderAction") {
diff --git a/crates/engine/src/cmd/rig3d.rs b/crates/engine/src/cmd/rig3d.rs
index f034fa641..5b17fcffe 100644
--- a/crates/engine/src/cmd/rig3d.rs
+++ b/crates/engine/src/cmd/rig3d.rs
@@ -48,7 +48,16 @@ impl Env {
         Env { time: s.time_of(cid), expr: s.expr.clone(), footage: s.footage.clone() }
     }
     fn ctx<'a>(&'a self, proj: &'a Project, cid: ItemId, comp: &'a Comp) -> EvalCtx<'a> {
-        EvalCtx { project: proj, comp_id: cid, comp, time: self.time, expr: self.expr.as_deref(), footage: Some(self.footage.as_ref()) }
+        EvalCtx {
+            project: proj,
+            comp_id: cid,
+            comp,
+            time: self.time,
+            expr: self.expr.as_deref(),
+            footage: Some(self.footage.as_ref()),
+            property_overrides: &[],
+            media_overrides: &[],
+        }
     }
 }
 
diff --git a/crates/engine/src/cmd/shape_tool.rs b/crates/engine/src/cmd/shape_tool.rs
index e1f3607b1..3323d61d6 100644
--- a/crates/engine/src/cmd/shape_tool.rs
+++ b/crates/engine/src/cmd/shape_tool.rs
@@ -180,16 +180,17 @@ fn rgba(c: [f32; 3]) -> [f64; 4] {
     [c[0] as f64, c[1] as f64, c[2] as f64, 1.0]
 }
 
-/// The Rounded Rectangle tool's corner roundness for `size`.
-fn roundness(size: [f64; 2]) -> f64 {
-    size[0].min(size[1]) * 0.15
+/// The Rounded Rectangle tool's corner roundness: a fixed default, as in After Effects
+/// (it does not grow with the drawn size).
+fn roundness() -> f64 {
+    20.0
 }
 
 /// The Polygon and Star tools' Polystar for `size`: (star, points, outer radius, inner radius).
 fn polystar_of(kind: &str, size: [f64; 2]) -> Option<(bool, f64, f64, f64)> {
     match kind {
         "star" => Some((true, 5.0, size[0] / 2.0, size[0] / 4.0)),
-        "polygon" => Some((false, 6.0, size[0] / 2.0, 0.0)),
+        "polygon" => Some((false, 5.0, size[0] / 2.0, 0.0)),
         _ => None,
     }
 }
@@ -199,7 +200,7 @@ fn polystar_of(kind: &str, size: [f64; 2]) -> Option<(bool, f64, f64, f64)> {
 pub(crate) fn shape_group(ids: &mut Ids, kind: &str, size: [f64; 2], paint: &ShapeTool) -> Option<PropGroup> {
     let (path, gname) = match kind {
         "rect" | "rectangle" => (build::shape_rect(ids, size, [0.0, 0.0], 0.0), "Rectangle 1"),
-        "rounded" | "roundedRect" => (build::shape_rect(ids, size, [0.0, 0.0], roundness(size)), "Rectangle 1"),
+        "rounded" | "roundedRect" => (build::shape_rect(ids, size, [0.0, 0.0], roundness()), "Rectangle 1"),
         "ellipse" => (build::shape_ellipse(ids, size, [0.0, 0.0]), "Ellipse 1"),
         k => {
             let (star, points, outer, inner) = polystar_of(k, size)?;
@@ -218,7 +219,7 @@ pub fn mask_path(kind: &str, centre: [f64; 2], size: [f64; 2]) -> Option<ShapePa
     let bez = match kind {
         "rect" | "rectangle" => return Some(ShapePath::rect(centre, size[0], size[1])),
         "ellipse" => return Some(ShapePath::ellipse(centre, size[0], size[1])),
-        "rounded" | "roundedRect" => effectcraft_path::rect(size, centre, roundness(size)),
+        "rounded" | "roundedRect" => effectcraft_path::rect(size, centre, roundness()),
         k => {
             let (star, points, outer, inner) = polystar_of(k, size)?;
             effectcraft_path::polystar(effectcraft_path::Polystar {
diff --git a/crates/engine/src/cmd/text_anim.rs b/crates/engine/src/cmd/text_anim.rs
index 92ab23f17..296dc4c37 100644
--- a/crates/engine/src/cmd/text_anim.rs
+++ b/crates/engine/src/cmd/text_anim.rs
@@ -142,6 +142,7 @@ fn add_animator_prop(s: &mut Session, p: &Value) -> Result<Value> {
     }
     let layer = s.project.comp(cid).and_then(|c| c.layer(lid)).cloned().ok_or_else(|| bad(C, "no layer"))?;
     let auid = animator_uid(s, &layer, p, C)?;
+    let mut index = 0;
     s.edit("Add Text Animator Property", None, |proj, _| {
         let mut next = proj.next_id;
         let mut ids = Ids(&mut next);
@@ -151,10 +152,13 @@ fn add_animator_prop(s: &mut Session, p: &Value) -> Result<Value> {
         for k in &kinds {
             add_props(&mut ids, anim, k, three);
         }
+        // The requested property's 1-based position in the Properties group. A companion (such as
+        // Tracking Type) is added before it, so the first new child is not always the one asked for.
+        index = kinds.first().and_then(|k| anim.sub("properties")?.children.iter().position(|n| n.match_id() == k.as_str())).map_or(0, |i| i + 1);
         proj.next_id = next;
         Ok(())
     })?;
-    Ok(json!({"animator": auid}))
+    Ok(json!({"animator": auid, "index": index}))
 }
 
 pub(crate) fn add_selector(s: &mut Session, p: &Value) -> Result<Value> {
diff --git a/crates/engine/src/cmd/text_edit.rs b/crates/engine/src/cmd/text_edit.rs
index 0d9b25aec..cdb650486 100644
--- a/crates/engine/src/cmd/text_edit.rs
+++ b/crates/engine/src/cmd/text_edit.rs
@@ -71,7 +71,8 @@ pub struct TextEdit {
     /// Character panel changes made with only a caret: the style the next typed text takes.
     #[serde(default)]
     pub pending: Option<CharStyle>,
-    /// The layer was made by a Type tool click; leaving it empty deletes it.
+    /// The layer was made by a Type tool click. Kept when left empty, as After Effects does, so this
+    /// only records how the edit began.
     #[serde(default)]
     pub created: bool,
     /// Line position kept by repeated up / down moves (layout space).
@@ -372,18 +373,14 @@ fn edit(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(state_json(s))
 }
 
-/// `text.endEdit`: stop editing (a Type-tool layer left empty is deleted).
+/// `text.endEdit`: stop editing.
+///
+/// A Type-tool layer the user clicked away from without typing is **kept**: After Effects leaves it in
+/// the timeline as `<空白のテキストレイヤー>`, and the layer came from the user's click rather than from a
+/// mistake to clean up. Deleting it took away something they could still type into.
 pub(crate) fn end_edit(s: &mut Session, _: &Value) -> Result<Value> {
-    let Some(e) = s.state.text_edit.take() else { return Ok(Value::Null) };
-    if e.created && layer_doc(s, e.layer).is_some_and(|d| d.text.is_empty()) {
-        let cid = s.active_comp_id().ok_or(EngineError::NoComp)?;
-        s.edit("Delete Empty Text Layer", None, |proj, st| {
-            if let Some(c) = proj.comp_mut(cid) {
-                c.layers.retain(|l| l.id != e.layer);
-            }
-            st.selected_layers.retain(|l| *l != e.layer);
-            Ok(())
-        })?;
+    if s.state.text_edit.take().is_none() {
+        return Ok(Value::Null);
     }
     s.bump();
     Ok(Value::Null)
diff --git a/crates/engine/src/cmd/three_d.rs b/crates/engine/src/cmd/three_d.rs
index e143690d3..1cf470ebe 100644
--- a/crates/engine/src/cmd/three_d.rs
+++ b/crates/engine/src/cmd/three_d.rs
@@ -413,7 +413,8 @@ fn get_3d(s: &mut Session, p: &Value) -> Result<Value> {
     let (w, h) = (comp.width as f64, comp.height as f64);
     let vs = s.state.views3d.get(&cid).cloned().unwrap_or_default();
     let t = s.state.times.get(&cid).copied().unwrap_or(Tick::ZERO);
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let cam = vs.override_camera(w, h).unwrap_or_else(|| camera::active_camera(&ctx));
     let f = cam.forward();
     let lights: Vec<Value> = comp
@@ -555,7 +556,8 @@ fn auto_orient(s: &mut Session, p: &Value) -> Result<Value> {
 /// through each layer's world matrix; cameras and lights contribute their position).
 fn layer_points(s: &Session, cid: ItemId, ids: &[LayerId], t: Tick) -> Vec<Vec3> {
     let Some(comp) = s.project.comp(cid) else { return vec![] };
-    let ctx = EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None };
+    let ctx =
+        EvalCtx { project: &s.project, comp_id: cid, comp, time: t, expr: s.expr.as_deref(), footage: None, property_overrides: &[], media_overrides: &[] };
     let mut out = vec![];
     for l in comp.layers.iter().filter(|l| ids.contains(&l.id)) {
         let m = ctx.world_matrix(l);
diff --git a/crates/engine/src/footage/footage_reload.rs b/crates/engine/src/footage/footage_reload.rs
index 75fd0f936..267985e37 100644
--- a/crates/engine/src/footage/footage_reload.rs
+++ b/crates/engine/src/footage/footage_reload.rs
@@ -81,6 +81,8 @@ fn refreshed(s: &Session, f: &Footage, probed: Footage) -> Footage {
     nf.codec = probed.codec;
     nf.has_video = probed.has_video;
     nf.has_audio = probed.has_audio;
+    // The markers the file carries now (a WAV's cue points), for Update Markers From Source.
+    nf.markers = probed.markers;
     if matches!(f.kind, FootageKind::Video | FootageKind::Audio) {
         nf.duration = probed.duration;
         // Interpret Footage ▸ Conform to frame rate stays; the file's own rate is refreshed.
diff --git a/crates/engine/src/settings/prefs/dialog.rs b/crates/engine/src/settings/prefs/dialog.rs
index e3f2006d8..d330ce190 100644
--- a/crates/engine/src/settings/prefs/dialog.rs
+++ b/crates/engine/src/settings/prefs/dialog.rs
@@ -122,6 +122,11 @@ pub fn pages() -> Vec<Page> {
                 Section("New Project"),
                 s("project.useTemplate", "New Project Loads Template", B, true),
                 s("project.templatePath", "Template Project", Kind::Path, true),
+                Section("Project Files"),
+                s("project.compactProjectFiles", "Save Compact Project Files", B, true),
+                Note(
+                    "Saves .ecproj files as compact JSON on one line: smaller and faster to save and open, but hard to read or diff in version control. Off, they are indented, one value per line.",
+                ),
                 Section("Auto-Save"),
                 s("autoSave.enabled", "Automatically Save Projects", B, true),
                 s("autoSave.intervalMinutes", "Save Every", Kind::Int(1, 240, "Minutes"), true),
diff --git a/crates/engine/src/settings/prefs/sections.rs b/crates/engine/src/settings/prefs/sections.rs
index e0bea8b85..aa683e2b8 100644
--- a/crates/engine/src/settings/prefs/sections.rs
+++ b/crates/engine/src/settings/prefs/sections.rs
@@ -62,6 +62,9 @@ page!(ProjectPrefs {
     /// Open a template project for File ▸ New ▸ New Project.
     use_template: bool = false,
     template_path: String = String::new(),
+    /// Write `.ecproj` files as compact JSON on one line (smaller, faster to save and open). Off:
+    /// indented, one value per line, so they read and diff cleanly in version control.
+    compact_project_files: bool = false,
 });
 
 page!(AutoSave {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 25237493c..25d05b903 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -15,6 +15,7 @@ mod frame_export;
 mod fuzz_open;
 mod history;
 mod import_project;
+mod instance3d;
 mod key_metadata_order;
 mod key_time;
 mod keyframe_text;
diff --git a/crates/engine/src/tests/crypto_pick.rs b/crates/engine/src/tests/crypto_pick.rs
index eacae55af..2e61f57a1 100644
--- a/crates/engine/src/tests/crypto_pick.rs
+++ b/crates/engine/src/tests/crypto_pick.rs
@@ -190,7 +190,16 @@ fn rendered_matte_of_pick(s: &mut Session, x: f64, y: f64, scale: f64) -> (Strin
     s.execute_checked("prop.set", json!({"path": format!("effects/#{fx}/matteOnly"), "value": true})).unwrap();
     let (cid, comp) = (s.active_comp_id().unwrap(), s.active_comp().unwrap());
     let layer = &comp.layers[0];
-    let ctx = effectcraft_render::EvalCtx { project: &s.project, comp_id: cid, comp, time: Tick::ZERO, expr: None, footage: None };
+    let ctx = effectcraft_render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let buf = s.renderer(effectcraft_render::RenderOpts { scale, ..Default::default() }).content_buf(&ctx, layer).unwrap();
     let (px, py) = buf.to_px([x, y]);
     let m = buf.img.get(px.floor() as i64, py.floor() as i64)[0];
diff --git a/crates/engine/src/tests/essential.rs b/crates/engine/src/tests/essential.rs
index 191416b9d..db5bf0751 100644
--- a/crates/engine/src/tests/essential.rs
+++ b/crates/engine/src/tests/essential.rs
@@ -367,6 +367,128 @@ fn media_replacement_swaps_footage_per_instance() {
     assert!(center(&s, main)[0] > 0.99);
 }
 
+/// #1747: a collapsed precomp with an Essential Property override must keep drawing its nested
+/// layers past the precomp's frame instead of falling back to a flattened, clipped frame.
+#[test]
+fn collapsed_precomp_applies_property_overrides_without_clipping() {
+    struct AddY;
+    impl effectcraft_render::ExprHost for AddY {
+        fn eval(
+            &self,
+            _: &effectcraft_render::EvalCtx,
+            _: &effectcraft_project::Layer,
+            _: &effectcraft_project::Property,
+            value: &effectcraft_keyframe::Value,
+        ) -> Result<effectcraft_keyframe::Value, String> {
+            Ok(match value {
+                effectcraft_keyframe::Value::Vec3([x, y, z]) => effectcraft_keyframe::Value::Vec3([*x, y + 100.0, *z]),
+                _ => value.clone(),
+            })
+        }
+    }
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Inner", "width": 400, "height": 300, "frameRate": 30, "duration": 2})).unwrap();
+    let inner = s.active_comp_id().unwrap();
+    let box_ = s.execute("layer.newSolid", json!({"name": "Box", "color": "#ffffff", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": box_, "path": "transform/position", "value": [200, 50, 0]})).unwrap();
+    // The source property's expression still runs after the instance override.
+    s.execute("prop.setExpression", json!({"layer": box_, "path": "transform/position", "expression": "value + [0, 100, 0]"})).unwrap();
+    let position = s.execute("essential.addProperty", json!({"layer": box_, "path": "transform/position"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Outer", "width": 400, "height": 600, "frameRate": 30, "duration": 2})).unwrap();
+    let outer = s.active_comp_id().unwrap();
+    let instance = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    let other = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [instance, other], "switch": "collapse", "value": true})).unwrap();
+    s.expr = Some(std::sync::Arc::new(AddY));
+    s.execute("layer.select", json!({"layers": [instance]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": position, "value": [200, -120, 0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [other]})).unwrap();
+    s.execute("essential.set", json!({"layer": other, "control": position, "value": [200, 220, 0]})).unwrap();
+    let img = s.render(outer, Tick::ZERO, RenderOpts::default());
+    // The expression adds 100 px: the overrides give inner y = -20 and 320. The first maps to
+    // outer y = 130 (the precomp is centred at 300) and its 100 px box spans 80..179, 70 px above
+    // the instance's frame (150..449), where a flattened precomp would stop. The second maps to
+    // 470 and spans 420..519, past the bottom.
+    assert!(img.get(200, 100)[3] > 0.99, "the override draws above the nested frame: {:?}", img.get(200, 100));
+    assert!(img.get(200, 90)[3] > 0.99, "the box reaches the top of its overridden bounds");
+    assert!(img.get(200, 500)[3] > 0.99, "the other instance keeps its own override: {:?}", img.get(200, 500));
+    assert!(img.get(200, 200)[3] < 0.01, "nothing is left between the instances");
+}
+
+/// #1747: two collapsed instances of the same comp keep their own source-affecting property
+/// overrides in the layer cache (the nested layers' ids and static values are identical).
+#[test]
+fn collapsed_instances_keep_distinct_property_overrides_in_the_cache() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Card", "width": 64, "height": 64, "frameRate": 30, "duration": 2})).unwrap();
+    let card = s.active_comp_id().unwrap();
+    let solid = s.execute("layer.newSolid", json!({"name": "BG", "color": "#ffffff", "width": 64, "height": 64})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("effect.apply", json!({"layer": solid, "effect": "Fill"})).unwrap();
+    let color = s.execute("essential.addProperty", json!({"layer": solid, "path": "effects/#1/color"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Main", "width": 200, "height": 100, "frameRate": 30, "duration": 2})).unwrap();
+    let main = s.active_comp_id().unwrap();
+    let a = s.execute("layer.addItem", json!({"item": card.0})).unwrap()["layer"].as_u64().unwrap();
+    let b = s.execute("layer.addItem", json!({"item": card.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [a, b], "switch": "collapse", "value": true})).unwrap();
+    s.execute("prop.set", json!({"layer": a, "path": "transform/position", "value": [60, 50, 0]})).unwrap();
+    s.execute("prop.set", json!({"layer": b, "path": "transform/position", "value": [140, 50, 0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [a]})).unwrap();
+    s.execute("essential.set", json!({"layer": a, "control": color, "value": [1.0, 0.0, 0.0, 1.0]})).unwrap();
+    s.execute("layer.select", json!({"layers": [b]})).unwrap();
+    s.execute("essential.set", json!({"layer": b, "control": color, "value": [0.0, 0.0, 1.0, 1.0]})).unwrap();
+    let img = s.render(main, Tick::ZERO, RenderOpts::default());
+    let left = img.get(60, 50);
+    let right = img.get(140, 50);
+    assert!(left[0] > 0.99 && left[2] < 0.01, "left instance is red: {left:?}");
+    assert!(right[2] > 0.99 && right[0] < 0.01, "right instance is blue: {right:?}");
+}
+
+/// #1747 with Media Replacement: the replacement footage and the position override both apply
+/// while the precomp stays collapsed, so the box is blue and still draws above the frame.
+#[test]
+fn collapsed_precomp_applies_media_replacement_without_clipping() {
+    struct Colors;
+    impl crate::render::FootageSource for Colors {
+        fn frame(&self, _: ItemId, f: &effectcraft_project::Footage, _: Tick) -> Option<std::sync::Arc<effectcraft_raster::Image>> {
+            let c = if f.path.contains("blue") { [0.0, 0.0, 1.0, 1.0] } else { [1.0, 0.0, 0.0, 1.0] };
+            Some(std::sync::Arc::new(effectcraft_raster::Image::filled(100, 100, c)))
+        }
+    }
+    let mut s = Session { footage: std::sync::Arc::new(Colors), ..Default::default() };
+    let footage = |path: &str| effectcraft_project::Footage {
+        path: path.into(),
+        kind: effectcraft_project::FootageKind::Still,
+        width: 100,
+        height: 100,
+        has_video: true,
+        ..Default::default()
+    };
+    let (red, blue) = s
+        .edit("test", None, |proj, _| {
+            let red = proj.add_item("red.png", Default::default(), None, effectcraft_project::ItemKind::Footage(footage("red.png")));
+            let blue = proj.add_item("blue.png", Default::default(), None, effectcraft_project::ItemKind::Footage(footage("blue.png")));
+            Ok((red, blue))
+        })
+        .unwrap();
+    s.execute("comp.new", json!({"name": "Inner", "width": 400, "height": 300, "frameRate": 30, "duration": 2})).unwrap();
+    let inner = s.active_comp_id().unwrap();
+    let clip = s.execute("layer.addItem", json!({"item": red.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": clip, "path": "transform/position", "value": [200, 50, 0]})).unwrap();
+    let media = s.execute("essential.addMedia", json!({"layer": clip})).unwrap()["control"].as_u64().unwrap();
+    let position = s.execute("essential.addProperty", json!({"layer": clip, "path": "transform/position"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Outer", "width": 400, "height": 600, "frameRate": 30, "duration": 2})).unwrap();
+    let outer = s.active_comp_id().unwrap();
+    let instance = s.execute("layer.addItem", json!({"item": inner.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [instance], "switch": "collapse", "value": true})).unwrap();
+    s.execute("layer.select", json!({"layers": [instance]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": position, "value": [200, -20, 0]})).unwrap();
+    s.execute("essential.set", json!({"layer": instance, "control": media, "item": blue.0})).unwrap();
+    let img = s.render(outer, Tick::ZERO, RenderOpts::default());
+    let above = img.get(200, 100);
+    assert!(above[2] > 0.99 && above[0] < 0.01, "the replacement media is blue above the frame: {above:?}");
+    assert!(img.get(200, 200)[3] < 0.01, "the collapsed box is not clipped at the nested frame");
+}
+
 /// Responsive Design — Time: stretching a precomp keeps its protected regions at their
 /// original speed; the unprotected parts absorb the stretch.
 #[test]
diff --git a/crates/engine/src/tests/essential_more.rs b/crates/engine/src/tests/essential_more.rs
index a8d8dc808..ea4aa42e5 100644
--- a/crates/engine/src/tests/essential_more.rs
+++ b/crates/engine/src/tests/essential_more.rs
@@ -2,6 +2,7 @@
 
 use effectcraft_keyframe::Value as KV;
 use effectcraft_project::essential::{self, ControlType};
+use effectcraft_time::Tick;
 use serde_json::json;
 
 use crate::{Event, Session};
@@ -102,3 +103,33 @@ fn open_in_essential_graphics_sets_the_primary_comp() {
     );
     assert_eq!(s.execute("essential.list", json!({})).unwrap()["name"], "A");
 }
+
+/// #1747: through a collapsed precomp, a Text override and a Font override of the same Source
+/// Text both apply: the Font merges into the overridden text, as `essential::with_overrides`
+/// does on the flattened path, instead of one entry replacing the other.
+#[test]
+fn collapsed_instance_merges_text_and_font_overrides() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Title", "width": 64, "height": 64, "frameRate": 30, "duration": 1})).unwrap();
+    let title = s.active_comp_id().unwrap();
+    let text = s.execute("layer.newText", json!({"text": "Hello"})).unwrap()["layer"].as_u64().unwrap();
+    let body = s.execute("essential.addProperty", json!({"layer": text, "path": "text/sourceText"})).unwrap()["controls"][0].as_u64().unwrap();
+    let font = s.execute("essential.addProperty", json!({"layer": text, "path": "text/sourceText", "as": "font"})).unwrap()["controls"][0].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Main", "width": 64, "height": 64, "frameRate": 30, "duration": 1})).unwrap();
+    let main = s.active_comp_id().unwrap();
+    let inst = s.execute("layer.addItem", json!({"item": title.0})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [inst], "switch": "collapse", "value": true})).unwrap();
+    s.execute("essential.set", json!({"layer": inst, "control": body, "value": "Bye"})).unwrap();
+    s.execute("essential.set", json!({"layer": inst, "control": font, "value": {"font": "Serif Test", "size": 40}})).unwrap();
+    // Evaluate the nested text in the collapsed instance's context, as the renderer does.
+    let r = effectcraft_render::Renderer::new(&s.project, &*s.footage, crate::render::RenderOpts::default());
+    let ctx = effectcraft_render::EvalCtx::new(&s.project, main, s.project.comp(main).unwrap(), Tick::ZERO);
+    let layer = ctx.comp.layer(effectcraft_project::LayerId(inst)).unwrap();
+    let collapsed = r.collapsed(&ctx, layer).expect("the instance collapses");
+    let (_, nctx) = r.collapse_into(&ctx, layer, &collapsed, 1.0).expect("a nested context");
+    let src = nctx.comp.layer(effectcraft_project::LayerId(text)).unwrap();
+    match nctx.value(src, src.props.prop("text/sourceText").unwrap()) {
+        KV::Text(d) => assert_eq!((d.text.as_str(), d.font.as_str(), d.size), ("Bye", "Serif Test", 40.0)),
+        o => panic!("{o:?}"),
+    }
+}
diff --git a/crates/engine/src/tests/frame_export.rs b/crates/engine/src/tests/frame_export.rs
index a45c5d444..a8dc938fb 100644
--- a/crates/engine/src/tests/frame_export.rs
+++ b/crates/engine/src/tests/frame_export.rs
@@ -164,3 +164,69 @@ fn copy_frame_hands_the_rendered_frame_to_the_frontend() {
     assert!(Session::default().execute("comp.copyFrame", json!({})).is_err());
     assert!(crate::menus::entries().iter().any(|(path, e)| e.command == "comp.copyFrame" && path.first().map(String::as_str) == Some("Composition")));
 }
+
+#[test]
+fn save_frame_as_png_preserves_alpha_channel() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "AlphaComp", "width": 32, "height": 32, "frameRate": 24, "duration": 1})).unwrap();
+    let red = s.execute("layer.newSolid", json!({"name": "Red", "color": "#ff0000", "width": 16, "height": 16})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": red, "path": "transform/position", "value": [8, 8, 0]})).unwrap();
+    let dir = out_dir("frame-png-alpha");
+    let path = dir.join("alpha.png").to_string_lossy().to_string();
+
+    s.execute("comp.saveFrameAs", json!({"path": path})).unwrap();
+    let img = image::load_from_memory(&std::fs::read(&path).unwrap()).unwrap().to_rgba8();
+    assert_eq!((img.width(), img.height()), (32, 32));
+    let solid_px = img.get_pixel(8, 8);
+    assert_eq!(solid_px[3], 255, "solid region must be opaque: {solid_px:?}");
+    assert_eq!(solid_px[0], 255);
+    let empty_px = img.get_pixel(24, 24);
+    assert_eq!(empty_px[3], 0, "outside solid region must have alpha 0: {empty_px:?}");
+
+    let flat_path = dir.join("flat.png").to_string_lossy().to_string();
+    s.execute_checked("comp.saveFrameAs", json!({"path": flat_path, "transparent": false})).unwrap();
+    let flat_img = image::load_from_memory(&std::fs::read(&flat_path).unwrap()).unwrap().to_rgba8();
+    let flat_empty_px = flat_img.get_pixel(24, 24);
+    assert_eq!(flat_empty_px[3], 255, "transparent: false must composite over background: {flat_empty_px:?}");
+}
+
+#[test]
+fn save_frame_as_queued_respects_frame_default_template() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Comp", "width": 32, "height": 32, "frameRate": 24, "duration": 1})).unwrap();
+
+    // Default Still template is "PNG Sequence" (Channels::Rgb)
+    let r = s.execute_checked("comp.saveFrameAs", json!({"queue": true})).unwrap();
+    assert_eq!(r["queued"], true);
+    let it = s.project.render_queue.last().unwrap();
+    assert_eq!(it.output.name, "PNG Sequence");
+    assert_eq!(it.output.channels, effectcraft_project::render_queue::Channels::Rgb);
+
+    // Test undo and redo of queuing a frame
+    s.execute("edit.undo", json!({})).unwrap();
+    assert!(s.project.render_queue.is_empty());
+    s.execute("edit.redo", json!({})).unwrap();
+    let it = s.project.render_queue.last().unwrap();
+    assert_eq!(it.output.name, "PNG Sequence");
+
+    // Explicit transparent: false forces Channels::Rgb
+    s.execute_checked("comp.saveFrameAs", json!({"queue": true, "transparent": false})).unwrap();
+    let it = s.project.render_queue.last().unwrap();
+    assert_eq!(it.output.channels, effectcraft_project::render_queue::Channels::Rgb);
+
+    // When Frame Default is set to an RGBA template, it is respected
+    s.execute_checked("renderQueue.setTemplateDefault", json!({"kind": "outputModule", "slot": "still", "name": "PNG Sequence with Alpha"})).unwrap();
+    s.execute_checked("comp.saveFrameAs", json!({"queue": true})).unwrap();
+    let it = s.project.render_queue.last().unwrap();
+    assert_eq!(it.output.name, "PNG Sequence with Alpha");
+    assert_eq!(it.output.channels, effectcraft_project::render_queue::Channels::Rgba);
+
+    // Passing transparent: false forces Channels::Rgb even with an RGBA template
+    s.execute_checked("comp.saveFrameAs", json!({"queue": true, "transparent": false})).unwrap();
+    let it = s.project.render_queue.last().unwrap();
+    assert_eq!(it.output.channels, effectcraft_project::render_queue::Channels::Rgb);
+
+    // With JPEG Sequence as Frame Default (non-alpha format), queue succeeds without error
+    s.execute_checked("renderQueue.setTemplateDefault", json!({"kind": "outputModule", "slot": "still", "name": "JPEG Sequence"})).unwrap();
+    assert!(s.execute_checked("comp.saveFrameAs", json!({"queue": true})).is_ok());
+}
diff --git a/crates/engine/src/tests/instance3d.rs b/crates/engine/src/tests/instance3d.rs
new file mode 100644
index 000000000..48f4b7730
--- /dev/null
+++ b/crates/engine/src/tests/instance3d.rs
@@ -0,0 +1,257 @@
+//! Create 3D Layer Instance (Layer ▸ Create): a comp-sized solid at the top of the layer stack
+//! with a 3D Layer Instance effect referencing the selected 3D model layer — a 2D copy of its
+//! render that 2D effects can be applied to (behaviour, pixels, undo/redo, serde).
+
+use std::sync::Arc;
+
+use effectcraft_keyframe::Value as KV;
+use effectcraft_project::{Footage, FootageKind, GroupKind, ItemId, Layer, LayerId, Project};
+use effectcraft_render::{FootageSource, RenderOpts};
+use effectcraft_time::{FrameRate, Tick};
+use serde_json::json;
+
+use crate::{Importer, Session};
+
+fn session() -> Session {
+    let mut s = Session { footage: Arc::new(DiskModels), importer: Some(Arc::new(ModelImporter)), ..Default::default() };
+    s.execute("comp.new", json!({"name": "Scene", "width": 640, "height": 360, "frameRate": 30, "duration": 2})).unwrap();
+    s
+}
+
+fn cid(s: &Session) -> ItemId {
+    s.active_comp_id().unwrap()
+}
+
+fn layer_in(s: &Session, comp: ItemId, id: u64) -> Layer {
+    s.project.comp(comp).unwrap().layer(LayerId(id)).unwrap().clone()
+}
+
+fn px(img: &effectcraft_raster::Image, x: u32, y: u32) -> [f32; 4] {
+    img.data[(y * img.width + x) as usize]
+}
+
+fn close(a: &effectcraft_raster::Image, b: &effectcraft_raster::Image, tol: f32) -> bool {
+    a.data.iter().zip(b.data.iter()).all(|(p, q)| p.iter().zip(q.iter()).all(|(x, y)| (x - y).abs() <= tol))
+}
+
+struct DiskModels;
+
+impl FootageSource for DiskModels {
+    fn frame(&self, _: ItemId, _: &Footage, _: Tick) -> Option<Arc<effectcraft_raster::Image>> {
+        None
+    }
+    fn model(&self, _: ItemId, f: &Footage) -> Option<Arc<effectcraft_model::Model>> {
+        let bytes = std::fs::read(&f.path).ok()?;
+        effectcraft_model::load(&f.path, &bytes, &|_| None).ok().map(Arc::new)
+    }
+}
+
+struct ModelImporter;
+
+impl Importer for ModelImporter {
+    fn probe(&self, path: &str) -> Result<Footage, String> {
+        effectcraft_model::format_of(path).ok_or("not a model")?;
+        Ok(Footage { path: path.into(), kind: FootageKind::Model, frame_rate: FrameRate::FPS_30, codec: "glTF".into(), ..Default::default() })
+    }
+}
+
+/// A red triangle in the Z = 0 plane (buffer embedded as a data URI).
+const TRIANGLE: &str = r#"{
+  "asset": {"version": "2.0"},
+  "scenes": [{"nodes": [0]}],
+  "nodes": [{"mesh": 0}],
+  "meshes": [{"primitives": [{"attributes": {"POSITION": 0, "NORMAL": 1}, "material": 0}]}],
+  "materials": [{"pbrMetallicRoughness": {"baseColorFactor": [1.0, 0.0, 0.0, 1.0]}}],
+  "buffers": [{"byteLength": 72, "uri": "data:application/octet-stream;base64,AACAvwAAgL8AAAAAAACAPwAAgL8AAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/"}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 36},
+    {"buffer": 0, "byteOffset": 36, "byteLength": 36}
+  ],
+  "accessors": [
+    {"bufferView": 0, "componentType": 5126, "type": "VEC3", "count": 3, "min": [-1.0, -1.0, 0.0], "max": [1.0, 1.0, 0.0]},
+    {"bufferView": 1, "componentType": 5126, "type": "VEC3", "count": 3}
+  ]
+}"#;
+
+fn triangle_model(s: &mut Session) -> u64 {
+    let dir = std::env::temp_dir().join(format!("ec-instance3d-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("Triangle.gltf");
+    std::fs::write(&path, TRIANGLE).unwrap();
+    s.execute("layer.newModel", json!({"path": path.to_string_lossy(), "name": "Triangle"})).unwrap()["layer"].as_u64().unwrap()
+}
+
+#[test]
+fn instance3d_creates_a_2d_copy_of_the_model() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    // The model renders through the comp's camera.
+    let before = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    assert!(px(&before, 320, 180)[3] > 0.9, "the model covers the centre: {:?}", px(&before, 320, 180));
+    assert!(px(&before, 4, 4)[3] < 0.1, "the comp is transparent around it: {:?}", px(&before, 4, 4));
+    // Create 3D Layer Instance.
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    let comp = cid(&s);
+    let l = layer_in(&s, comp, solid);
+    assert_eq!(l.name, "Triangle Instance");
+    assert_eq!(s.active_comp().unwrap().layers[0].id.0, solid, "at the top of the layer stack");
+    // A 3D Layer Instance effect referencing the 3D layer.
+    let g = l.effects().unwrap().groups().next().unwrap().clone();
+    assert!(matches!(&g.kind, GroupKind::Effect { effect } if effect == "ec.3d.instance3d"), "{:?}", g.kind);
+    assert_eq!(g.get("layer").unwrap().value, KV::Layer(Some(model)));
+    // The model is switched off, the copy selected.
+    assert!(!layer_in(&s, comp, model).switches.video, "the referenced 3D layer is off, as After Effects does");
+    assert_eq!(s.state.selected_layers, vec![LayerId(solid)]);
+    // The comp renders the same through the copy: a 2D copy of the 3D layer, transparent
+    // around it.
+    let after = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(close(&before, &after, 2e-2), "the copy shows the model:\n{:?}\n{:?}", px(&before, 320, 180), px(&after, 320, 180));
+    assert!(px(&after, 320, 180)[3] > 0.9 && px(&after, 4, 4)[3] < 0.1, "{:?} {:?}", px(&after, 320, 180), px(&after, 4, 4));
+    // Undo removes the copy and switches the model back on; redo returns it.
+    s.execute("edit.undo", json!({})).unwrap();
+    assert!(s.active_comp().unwrap().layer(LayerId(solid)).is_none());
+    assert!(layer_in(&s, comp, model).switches.video);
+    s.execute("edit.redo", json!({})).unwrap();
+    assert!(s.active_comp().unwrap().layer(LayerId(solid)).is_some());
+    assert!(!layer_in(&s, comp, model).switches.video);
+    // Serde round-trips the layer parameter.
+    let j = serde_json::to_string(&*s.project).unwrap();
+    let back: Project = serde_json::from_str(&j).unwrap();
+    assert_eq!(back, *s.project);
+    // 2D effects can be applied to the copy (the model layer itself takes none): Fill in blue
+    // recolours the triangle.
+    s.execute("effect.apply", json!({"layer": solid, "effect": "ec.generate.fill"})).unwrap();
+    s.execute("prop.set", json!({"layer": solid, "path": "effects/#2/color", "value": [0.0, 0.0, 1.0, 1.0]})).unwrap();
+    let with_fx = s.render(comp, Tick::ZERO, RenderOpts::default());
+    let p = px(&with_fx, 320, 180);
+    assert!(p[2] > 0.9 && p[0] < 0.1, "the fill recolours the copy: {p:?}");
+}
+
+#[test]
+fn instance3d_also_takes_3d_primitives() {
+    let mut s = session();
+    let prim = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 200, "height": 200, "depth": 200})).unwrap()["layer"].as_u64().unwrap();
+    let before = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [prim]})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    let l = layer_in(&s, cid(&s), solid);
+    assert_eq!(l.name, "Cube Instance");
+    assert!(!layer_in(&s, cid(&s), prim).switches.video);
+    let after = s.render(cid(&s), Tick::ZERO, RenderOpts::default());
+    assert!(close(&before, &after, 2e-2), "the copy shows the cube");
+}
+
+#[test]
+fn instance3d_needs_a_3d_layer() {
+    let mut s = session();
+    let solid = s.execute("layer.newSolid", json!({"color": "#808080", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    let err = s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [solid]}));
+    assert!(err.is_err());
+    let text = s.execute("layer.newText", json!({"text": "hi"})).unwrap()["layer"].as_u64().unwrap();
+    assert!(s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [text]})).is_err());
+    // A 3D-switched text layer is not a model layer either (it has 2D pixels of its own).
+    s.execute("layer.setSwitch", json!({"layers": [text], "switch": "threeD", "value": true})).unwrap();
+    assert!(s.execute_checked("layer.create", json!({"op": "instance3d", "layers": [text]})).is_err());
+}
+
+#[test]
+fn instance3d_creates_every_selected_copy_in_one_undo() {
+    let mut s = session();
+    let a = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 120, "height": 120, "depth": 120})).unwrap()["layer"].as_u64().unwrap();
+    let b = s.execute("layer.new3dPrimitive", json!({"kind": "cube", "width": 120, "height": 120, "depth": 120})).unwrap()["layer"].as_u64().unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [a, b]})).unwrap();
+    let copies = r["layers"].as_array().unwrap();
+    assert_eq!(copies.len(), 2);
+    let (ia, ib) = (copies[0].as_u64().unwrap(), copies[1].as_u64().unwrap());
+    let comp = cid(&s);
+    assert_ne!(ia, ib);
+    assert_ne!(layer_in(&s, comp, ia).name, layer_in(&s, comp, ib).name, "each copy has a name of its own");
+    // Both sources are off, both copies selected, above their sources in the stack.
+    assert!(!layer_in(&s, comp, a).switches.video && !layer_in(&s, comp, b).switches.video);
+    let mut sel = s.state.selected_layers.clone();
+    let mut want = vec![LayerId(ia), LayerId(ib)];
+    sel.sort_by_key(|l| l.0);
+    want.sort_by_key(|l| l.0);
+    assert_eq!(sel, want);
+    let c = s.active_comp().unwrap();
+    let pos = |id: u64| c.layers.iter().position(|l| l.id.0 == id).unwrap();
+    assert!(pos(ia) < pos(a) && pos(ib) < pos(b), "the copies sit above their sources");
+    // One undo removes both copies and switches both models back on; one redo returns them.
+    s.execute("edit.undo", json!({})).unwrap();
+    let c = s.active_comp().unwrap();
+    assert!(c.layer(LayerId(ia)).is_none() && c.layer(LayerId(ib)).is_none(), "one undo removes every instance");
+    assert!(layer_in(&s, comp, a).switches.video && layer_in(&s, comp, b).switches.video);
+    s.execute("edit.redo", json!({})).unwrap();
+    let c = s.active_comp().unwrap();
+    assert!(c.layer(LayerId(ia)).is_some() && c.layer(LayerId(ib)).is_some(), "one redo returns every instance");
+    assert!(!layer_in(&s, comp, a).switches.video && !layer_in(&s, comp, b).switches.video);
+}
+
+#[test]
+fn instance3d_in_a_mixed_selection_only_takes_the_models() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    let solid = s.execute("layer.newSolid", json!({"color": "#808080", "width": 100, "height": 100})).unwrap()["layer"].as_u64().unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d", "layers": [model, solid]})).unwrap();
+    let copies = r["layers"].as_array().unwrap();
+    assert_eq!(copies.len(), 1, "only the model gets a copy: {r}");
+    let copy = copies[0].as_u64().unwrap();
+    let comp = cid(&s);
+    assert!(!layer_in(&s, comp, model).switches.video, "the model is switched off");
+    assert!(layer_in(&s, comp, solid).switches.video, "the plain solid is untouched");
+    let skipped = r["skipped"].as_array().unwrap();
+    assert_eq!(skipped.len(), 1);
+    assert!(skipped[0].as_str().unwrap().contains("not a 3D model layer"), "{skipped:?}");
+    // The copy references the model, not the solid.
+    let l = layer_in(&s, comp, copy);
+    let g = l.effects().unwrap().groups().next().unwrap().clone();
+    assert_eq!(g.get("layer").unwrap().value, KV::Layer(Some(model)));
+}
+
+#[test]
+fn instance3d_shows_nothing_outside_the_source_layer_range() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    // The model's range ends at 1 s; the comp runs to 2 s.
+    let comp = cid(&s);
+    s.edit("trim", None, |p, _| {
+        p.comp_mut(comp).unwrap().layer_mut(LayerId(model)).unwrap().out_point = Tick::from_seconds_f64(1.0);
+        Ok(())
+    })
+    .unwrap();
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let _copy = r["layers"][0].as_u64().unwrap();
+    // Inside the model's range the copy shows it, transparent around it.
+    let inside = s.render(comp, Tick::from_seconds_f64(0.5), RenderOpts::default());
+    assert!(px(&inside, 320, 180)[3] > 0.9, "the copy shows the model: {:?}", px(&inside, 320, 180));
+    // After its out point the source has nothing to read: the copy is transparent.
+    let outside = s.render(comp, Tick::from_seconds_f64(1.5), RenderOpts::default());
+    assert!(outside.data.iter().all(|p| p[3] < 1e-3), "transparent after the source's out point: {:?}", px(&outside, 320, 180));
+}
+
+#[test]
+fn instance3d_keeps_the_copy_visible_when_the_source_is_soloed() {
+    let mut s = session();
+    let model = triangle_model(&mut s);
+    let comp = cid(&s);
+    // Solo the model, then create the instance: any_solo hides non-soloed layers and the
+    // source's video goes off, so the copy has to take the Solo over.
+    s.edit("solo", None, |p, _| {
+        p.comp_mut(comp).unwrap().layer_mut(LayerId(model)).unwrap().switches.solo = true;
+        Ok(())
+    })
+    .unwrap();
+    let before = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(px(&before, 320, 180)[3] > 0.9, "the soloed model shows: {:?}", px(&before, 320, 180));
+    s.execute("layer.select", json!({"layers": [model]})).unwrap();
+    let r = s.execute("layer.create", json!({"op": "instance3d"})).unwrap();
+    let solid = r["layers"][0].as_u64().unwrap();
+    assert!(layer_in(&s, comp, solid).switches.solo, "the copy takes the source's Solo switch");
+    assert!(!layer_in(&s, comp, model).switches.video, "the source keeps its video off");
+    let after = s.render(comp, Tick::ZERO, RenderOpts::default());
+    assert!(px(&after, 320, 180)[3] > 0.9, "the soloed copy shows the model: {:?}", px(&after, 320, 180));
+    assert!(close(&before, &after, 2e-2), "the comp renders the same through the copy:\n{:?}\n{:?}", px(&before, 320, 180), px(&after, 320, 180));
+}
diff --git a/crates/engine/src/tests/menu_cmds.rs b/crates/engine/src/tests/menu_cmds.rs
index eb99d809f..93f81736f 100644
--- a/crates/engine/src/tests/menu_cmds.rs
+++ b/crates/engine/src/tests/menu_cmds.rs
@@ -1103,6 +1103,66 @@ fn transform_commands_keep_depth_and_follow_separated_dimensions() {
     assert_eq!(pos(&s, b)[..2], [200.0, 100.0], "the 200×100 solid's centre");
 }
 
+/// The layer's painted bounds mapped to comp space — what the viewer shows.
+fn seen_bounds(s: &Session, lid: u64) -> [f64; 4] {
+    let cid = s.active_comp_id().unwrap();
+    let comp = s.project.comp(cid).unwrap().clone();
+    let layer = comp.layer(effectcraft_project::LayerId(lid)).unwrap();
+    let ectx = effectcraft_render::EvalCtx::new(&s.project, cid, &comp, s.time());
+    let b = effectcraft_render::content_bounds(&ectx, layer).expect("painted bounds");
+    let m = ectx.layer_to_comp(layer).0;
+    let corners = [[b[0], b[1]], [b[2], b[1]], [b[2], b[3]], [b[0], b[3]]];
+    let pts: Vec<[f64; 2]> = corners
+        .iter()
+        .map(|p| {
+            let q = m.apply(effectcraft_geom::vec2(p[0], p[1]));
+            [q.x, q.y]
+        })
+        .collect();
+    let (mut x0, mut y0, mut x1, mut y1) = (f64::INFINITY, f64::INFINITY, f64::NEG_INFINITY, f64::NEG_INFINITY);
+    for p in &pts {
+        x0 = x0.min(p[0]);
+        y0 = y0.min(p[1]);
+        x1 = x1.max(p[0]);
+        y1 = y1.max(p[1]);
+    }
+    [x0, y0, x1, y1]
+}
+
+#[test]
+fn fit_to_comp_fills_the_comp_with_shape_and_text_bounds() {
+    let mut s = comp();
+    let close = |x: f64, y: f64| (x - y).abs() < 1e-6;
+    // A shape or text layer has no source item: fit sizes it by its painted bounds, anchored at
+    // the bounds' centre, so what the viewer shows fills the frame (#2198).
+    let a = s.execute("layer.newShape", json!({"kind": "rect", "size": [180, 80]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.transform", json!({"layers": [a], "op": "fit"})).unwrap();
+    let seen = seen_bounds(&s, a);
+    assert!(close(seen[0], 0.0) && close(seen[1], 0.0) && close(seen[2], 640.0) && close(seen[3], 360.0), "the rect's painted bounds fill the comp: {seen:?}");
+
+    let t = s.execute("layer.newText", json!({"text": "Title", "size": 80})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.transform", json!({"layers": [t], "op": "fit"})).unwrap();
+    let seen = seen_bounds(&s, t);
+    assert!(close(seen[0], 0.0) && close(seen[1], 0.0) && close(seen[2], 640.0) && close(seen[3], 360.0), "the text's painted bounds fill the comp: {seen:?}");
+
+    // fitWidth spans the comp's width and centres vertically.
+    for lid in [a, t] {
+        s.execute("layer.transform", json!({"layers": [lid], "op": "fitWidth"})).unwrap();
+        let seen = seen_bounds(&s, lid);
+        assert!(close(seen[0], 0.0) && close(seen[2], 640.0), "fitWidth spans the comp width: {seen:?}");
+        assert!(close((seen[1] + seen[3]) / 2.0, 180.0), "fitWidth centres vertically: {seen:?}");
+    }
+}
+
+#[test]
+fn fit_to_comp_refuses_a_scale_that_overflows() {
+    let mut s = comp();
+    let a = s.execute("layer.newShape", json!({"kind": "rect", "size": [1e-305, 80]})).unwrap()["layer"].as_u64().unwrap();
+    let before = s.project.clone();
+    assert!(s.execute("layer.transform", json!({"layers": [a], "op": "fit"})).is_err(), "an infinite scale is refused");
+    assert_eq!(s.project, before, "nothing was written");
+}
+
 #[test]
 fn duplicated_and_pasted_layers_keep_their_links() {
     let mut s = comp();
diff --git a/crates/engine/src/tests/rig3d.rs b/crates/engine/src/tests/rig3d.rs
index d801a743a..cf2518447 100644
--- a/crates/engine/src/tests/rig3d.rs
+++ b/crates/engine/src/tests/rig3d.rs
@@ -7,7 +7,7 @@ use std::sync::Arc;
 use effectcraft_geom::{Vec3, vec3};
 use effectcraft_keyframe::Value as KV;
 use effectcraft_project::{Footage, FootageKind, GroupKind, ItemId, Layer, LayerId, LayerSource, LightKind, Project};
-use effectcraft_render::three_d::camera::layer_frame;
+use effectcraft_render::three_d::camera::{is_two_node, layer_frame};
 use effectcraft_render::{EvalCtx, FootageSource, RenderOpts};
 use effectcraft_time::{FrameRate, Tick};
 use serde_json::{Value, json};
@@ -40,7 +40,7 @@ fn close3(a: [f64; 3], b: [f64; 3], tol: f64) -> bool {
 fn frame(s: &Session, id: u64) -> (Vec3, Vec3) {
     let c = cid(s);
     let comp = s.project.comp(c).unwrap();
-    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: Tick::ZERO, expr: None, footage: None, property_overrides: &[], media_overrides: &[] };
     let (e, f, _) = layer_frame(&ctx, comp.layer(LayerId(id)).unwrap());
     (e, f)
 }
@@ -217,8 +217,189 @@ fn control_light_with_camera_follows_and_releases() {
     assert!(s.execute("light.controlWithCamera", json!({"layers": [cam]})).is_err());
 }
 
+/// Parenting keeps a camera where it is (After Effects' Parent & Link): Position and Point of
+/// Interest are re-expressed in the null's space, so the frame does not move.
+#[test]
+fn parented_camera_keeps_its_frame_under_an_offset_null() {
+    let mut s = session();
+    let cam = camera(&mut s);
+    let (eye0, f0) = frame(&s, cam);
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 0]})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [cam], "parent": nul})).unwrap();
+    let (eye1, f1) = frame(&s, cam);
+    assert!((eye1 - eye0).length() < 1e-6 && (f1 - f0).length() < 1e-6, "{eye0:?} {eye1:?}");
+    // The null's origin is Position minus its default anchor (50, 50): (50, 10) in the comp.
+    let c = layer_in(&s, cid(&s), cam);
+    assert!(close3(v3(&c, "transform/position"), [270.0, 170.0, -800.0], 1e-6), "{:?}", v3(&c, "transform/position"));
+    assert!(close3(v3(&c, "transform/poi"), [270.0, 170.0, 0.0], 1e-6), "{:?}", v3(&c, "transform/poi"));
+    // Moving the null carries the camera and keeps its aim.
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [140, 90, 0]})).unwrap();
+    let (eye2, f2) = frame(&s, cam);
+    assert!((eye2 - (eye0 + vec3(40.0, 30.0, 0.0))).length() < 1e-6, "{eye2:?}");
+    assert!((f2 - f0).length() < 1e-6, "{f2:?}");
+}
+
+/// World (eye, forward, down) of a layer in the active comp at time `t`.
+fn frame_at(s: &Session, id: u64, t: Tick) -> (Vec3, Vec3, Vec3) {
+    let c = cid(s);
+    let comp = s.project.comp(c).unwrap();
+    let ctx = EvalCtx { project: &s.project, comp_id: c, comp, time: t, expr: None, footage: None, property_overrides: &[], media_overrides: &[] };
+    layer_frame(&ctx, comp.layer(LayerId(id)).unwrap())
+}
+
+/// Whether two frames agree on eye, forward and down.
+fn frames_match(a: (Vec3, Vec3, Vec3), b: (Vec3, Vec3, Vec3)) -> bool {
+    (a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 1e-6 && (a.2 - b.2).length() < 1e-6
+}
+
+/// A 3D null off-centre in the comp, with an Orientation and a Z rotation.
+fn rotated_null(s: &mut Session, orientation: [f64; 3], turn: f64) -> u64 {
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [nul], "switch": "threeD", "value": true})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 40]})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/orientation", "value": orientation})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/rotation", "value": turn})).unwrap();
+    nul
+}
+
+/// A two-node camera under a rotated null keeps its eye, aim and roll: its Orientation is
+/// re-expressed against the new aim, so Up does not drift.
+#[test]
+fn two_node_camera_under_rotated_null_keeps_its_roll() {
+    let mut s = session();
+    let cam = camera(&mut s);
+    s.execute("prop.set", json!({"layer": cam, "path": "transform/rotation", "value": 25})).unwrap();
+    assert!(is_two_node(&layer_in(&s, cid(&s), cam)));
+    let before = frame_at(&s, cam, Tick::ZERO);
+    let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [cam], "parent": nul})).unwrap();
+    let after = frame_at(&s, cam, Tick::ZERO);
+    assert!(frames_match(before, after), "{before:?} {after:?}");
+}
+
+#[test]
+fn parented_point_light_keeps_its_direction_under_a_rotated_null() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": light, "path": "transform/orientation", "value": [30, 0, 0]})).unwrap();
+    let (eye0, f0) = frame(&s, light);
+    let nul = s.execute("layer.newNull", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/position", "value": [100, 60, 0]})).unwrap();
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/rotation", "value": 30})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let (eye1, f1) = frame(&s, light);
+    assert!((eye1 - eye0).length() < 1e-6 && (f1 - f0).length() < 1e-6, "{eye0:?} {eye1:?} {f0:?} {f1:?}");
+}
+
+/// Keyed Orientation under a Z-only turn is shifted exactly, so the light keeps its direction at
+/// every time, between the keys too.
+#[test]
+fn keyed_orientation_under_a_z_turn_keeps_the_direction_at_every_time() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+    }
+    let times = [0.0, 0.25, 0.5, 0.75, 1.0].map(Tick::from_seconds_f64);
+    let before = times.map(|t| frame_at(&s, light, t));
+    let nul = rotated_null(&mut s, [0.0, 0.0, 0.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    for (t, b) in times.into_iter().zip(before) {
+        assert!(frames_match(b, frame_at(&s, light, t)), "a Z-only turn keeps the light's direction");
+    }
+}
+
+/// Under a tilted null the keys alone cannot follow (Euler angles are blended between them), so keys are
+/// added between them: the light keeps its direction within a small angle at every time.
+#[test]
+fn keyed_orientation_under_a_tilted_null_follows_between_the_keys() {
+    {
+        let mut s = session();
+        let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+        for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.5, json!([50.0, 118.0, 74.0]))] {
+            s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+        }
+        let times = [0.0, 0.2, 0.5, 0.9, 1.3, 1.5].map(Tick::from_seconds_f64);
+        let before = times.map(|t| frame_at(&s, light, t));
+        let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+        s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+        for (t, b) in times.into_iter().zip(before) {
+            let a = frame_at(&s, light, t);
+            // 0.05 degrees is about 9e-4 of a radian on a unit vector.
+            assert!((a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 2e-3, "at {t:?}: {:?} vs {:?}", a.1, b.1);
+        }
+        assert!(layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().keys.len() > 2, "keys were added between the two");
+    }
+}
+
+/// A one-node light parented under a mirrored null (Z scale -100%) keeps the Position and
+/// Orientation it was authored with: it has no Scale to carry the mirror, so none of it is
+/// compensated rather than reversing its frame (a half-compensated light would point backwards).
+#[test]
+fn one_node_light_under_a_mirrored_null_keeps_its_authored_values() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": light, "path": "transform/orientation", "value": [30, 0, 0]})).unwrap();
+    let before = layer_in(&s, cid(&s), light);
+    let nul = rotated_null(&mut s, [0.0, 0.0, 0.0], 0.0);
+    s.execute("prop.set", json!({"layer": nul, "path": "transform/scale", "value": [100, 100, -100]})).unwrap();
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let after = layer_in(&s, cid(&s), light);
+    assert_eq!(after.parent, Some(LayerId(nul)));
+    assert_eq!(v3(&after, "transform/position"), v3(&before, "transform/position"));
+    assert_eq!(v3(&after, "transform/orientation"), v3(&before, "transform/orientation"));
+}
+
+/// The cap on keys added by baking is for the whole Orientation property, not for each segment:
+/// many strongly eased segments under a tilted parent stay within it.
+#[test]
+fn baked_orientation_keys_are_capped_across_the_whole_property() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    let count = 120;
+    for i in 0..count {
+        let swing = if i % 2 == 0 { json!([0.0, 0.0, 0.0]) } else { json!([170.0, 60.0, 120.0]) };
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": i as f64 * 0.05, "value": swing})).unwrap();
+    }
+    let uid = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().uid;
+    let keys: Vec<_> = (0..count).map(|i| json!({"layer": light, "prop": uid, "time": i as f64 * 0.05})).collect();
+    s.execute("keys.select", json!({"keys": keys})).unwrap();
+    s.execute("keys.easyEase", json!({})).unwrap();
+    let nul = rotated_null(&mut s, [20.0, -35.0, 60.0], 30.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": nul})).unwrap();
+    let n = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().keys.len();
+    assert!(n <= 4096, "{n} keys: the cap is for the property, not per segment");
+    // the segments the cap left unchecked keep their authored easing instead of turning into straight blends
+    let orientation = layer_in(&s, cid(&s), light);
+    let keys = &orientation.props.prop("transform/orientation").unwrap().keys;
+    let last = keys.iter().rev().nth(1).expect("the penultimate key");
+    assert_ne!(last.out_interp, effectcraft_keyframe::Interp::Linear, "the last segment keeps its authored easing");
+}
+
 // ---------------------------------------------------------------- from 3D model
 
+/// Easy Ease agrees with a straight blend at the midpoint, but not at the quarter points.
+#[test]
+fn eased_orientation_under_x_parent_keeps_motion_between_keys() {
+    let mut s = session();
+    let light = s.execute("layer.newLight", json!({"kind": "Point", "position": [320, 180, -500]})).unwrap()["layer"].as_u64().unwrap();
+    for (time, value) in [(0.0, json!([0.0, 0.0, 0.0])), (1.0, json!([90.0, 0.0, 0.0]))] {
+        s.execute("prop.addKey", json!({"layer": light, "path": "transform/orientation", "time": time, "value": value})).unwrap();
+    }
+    let uid = layer_in(&s, cid(&s), light).props.prop("transform/orientation").unwrap().uid;
+    s.execute("keys.select", json!({"keys": [{"layer": light, "prop": uid, "time": 0.0}, {"layer": light, "prop": uid, "time": 1.0}]})).unwrap();
+    s.execute("keys.easyEase", json!({})).unwrap();
+    let times: Vec<_> = (0..=100).map(|i| Tick::from_seconds_f64(i as f64 / 100.0)).collect();
+    let before: Vec<_> = times.iter().map(|t| frame_at(&s, light, *t)).collect();
+    let parent = rotated_null(&mut s, [30.0, 0.0, 0.0], 0.0);
+    s.execute("layer.setParent", json!({"layers": [light], "parent": parent})).unwrap();
+    for (t, b) in times.into_iter().zip(before) {
+        let a = frame_at(&s, light, t);
+        assert!((a.0 - b.0).length() < 1e-6 && (a.1 - b.1).length() < 1e-3, "at {t:?}: {:?} vs {:?}", a.1, b.1);
+    }
+}
+
 struct DiskModels;
 
 impl FootageSource for DiskModels {
diff --git a/crates/engine/src/tests/sequence.rs b/crates/engine/src/tests/sequence.rs
index f2849a6be..cf6968e3f 100644
--- a/crates/engine/src/tests/sequence.rs
+++ b/crates/engine/src/tests/sequence.rs
@@ -182,14 +182,58 @@ fn interpret_footage_start_timecode_relabels_source_time() {
 }
 
 #[test]
-fn replace_footage_and_reload_keep_sequences() {
+fn replace_footage_keeps_a_still_a_still() {
     let dir = folder(&RUN);
     let mut s = session();
     let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": false})).unwrap()["items"][0].clone();
     s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    // Replacing with a numbered still does not silently turn the item into a sequence (#2073).
     s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png")})).unwrap();
     let (name, f) = footage(&s, &item);
-    assert_eq!((name.as_str(), f.sequence.len()), ("shot_[0001-0005].png", 4));
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // JSON null is unspecified, not "on": the still stays a still.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "sequence": null})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // Alphabetical is a sequence modifier, not a request to make one.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "alphabetical": true})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind), ("shot_0004.png", FootageKind::Still));
+    // Asking for the run still brings it.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png"), "sequence": true})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("shot_[0001-0005].png", FootageKind::Sequence, 4));
+}
+
+#[test]
+fn replace_footage_keeps_a_one_frame_run_a_sequence() {
+    let dir = folder(&["shot_0001.png", "shot_0002.png", "solo_0007.png", "cover.png"]);
+    let mut s = session();
+    let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": true})).unwrap()["items"][0].clone();
+    s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    // A numbered file with no other frame in its run is still the replacement for a sequence.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "solo_0007.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("solo_0007.png", FootageKind::Sequence, 1));
+    // A single-file source keeps the sequence kind too.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "cover.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("cover.png", FootageKind::Sequence, 1));
+    // An explicit `sequence: false` still asks for one frame.
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "cover.png"), "sequence": false})).unwrap();
+    let (_, f) = footage(&s, &item);
+    assert_eq!((f.kind, f.sequence.len()), (FootageKind::Still, 0));
+}
+
+#[test]
+fn replace_footage_and_reload_keep_sequences() {
+    let dir = folder(&RUN);
+    let mut s = session();
+    let item = s.execute("file.import", json!({"paths": [at(&dir, "shot_0001.png")], "sequence": true})).unwrap()["items"][0].clone();
+    s.state.project_selection = vec![ItemId(item.as_u64().unwrap())];
+    s.execute("file.replaceFootage", json!({"path": at(&dir, "shot_0004.png")})).unwrap();
+    let (name, f) = footage(&s, &item);
+    assert_eq!((name.as_str(), f.kind, f.sequence.len()), ("shot_[0001-0005].png", FootageKind::Sequence, 4));
     // Reload finds a new frame and keeps the interpretation.
     s.execute("file.interpretFootage", json!({"items": [item], "frameRate": 12, "startTimecode": 2})).unwrap();
     std::fs::write(at(&dir, "shot_0003.png"), b"").unwrap();
diff --git a/crates/engine/src/tests/session.rs b/crates/engine/src/tests/session.rs
index b5d1cbb5f..d4a47c1cc 100644
--- a/crates/engine/src/tests/session.rs
+++ b/crates/engine/src/tests/session.rs
@@ -476,6 +476,9 @@ fn set_text_paragraph_fill_and_leading() {
     s.execute("layer.setText", json!({"layer": t, "hScale": 120, "vScale": 80, "baselineShift": 4, "smallCaps": true, "strokeOverFill": true})).unwrap();
     let d = doc(&s);
     assert_eq!((d.h_scale, d.v_scale, d.baseline_shift, d.small_caps, d.stroke_over_fill), (120.0, 80.0, 4.0, true, true));
+    s.execute("layer.setText", json!({"layer": t, "lineJoin": "bevel"})).unwrap();
+    assert_eq!(doc(&s).line_join, effectcraft_keyframe::LineJoin::Bevel);
+    assert!(s.execute("layer.setText", json!({"layer": t, "lineJoin": "square"})).is_err());
 }
 
 #[test]
diff --git a/crates/engine/src/tests/settings.rs b/crates/engine/src/tests/settings.rs
index 81bed3c43..03003a77b 100644
--- a/crates/engine/src/tests/settings.rs
+++ b/crates/engine/src/tests/settings.rs
@@ -389,6 +389,23 @@ fn new_project_template_and_default_renderer() {
     let _ = std::fs::remove_dir_all(d);
 }
 
+#[test]
+fn project_files_are_indented_unless_compact_is_on() {
+    let d = tmp("compact-project-files");
+    let path = d.join("p.ecproj");
+    let mut s = session_with_comp();
+    s.execute("file.saveAs", json!({"path": path.to_string_lossy()})).unwrap();
+    let pretty = std::fs::read_to_string(&path).unwrap();
+    assert!(pretty.starts_with("{\n  \"savedBy\""), "indented by default");
+    s.execute("prefs.set", json!({"key": "project.compactProjectFiles", "value": true})).unwrap();
+    s.execute("file.saveAs", json!({"path": path.to_string_lossy()})).unwrap();
+    let compact = std::fs::read_to_string(&path).unwrap();
+    assert!(!compact.contains('\n'), "one line when Save Compact Project Files is on");
+    let open = |text: &str| effectcraft_project::Project::from_json(text).unwrap();
+    assert_eq!(open(&compact), open(&pretty), "both read back as the same project");
+    let _ = std::fs::remove_dir_all(d);
+}
+
 // ---------------------------------------------------------------- shortcuts
 
 #[test]
diff --git a/crates/engine/src/tests/shortcut_cmds.rs b/crates/engine/src/tests/shortcut_cmds.rs
index dd306ef93..c11885db1 100644
--- a/crates/engine/src/tests/shortcut_cmds.rs
+++ b/crates/engine/src/tests/shortcut_cmds.rs
@@ -184,6 +184,28 @@ fn in_and_out_points_stretch_to_the_current_time() {
     assert!(s.execute("layer.timeStretch", json!({"to": "middle"})).is_err());
 }
 
+#[test]
+fn trimming_out_to_the_playhead_keeps_its_frame_visible() {
+    let (mut s, ids) = session([(1.0, 9.0); 3]);
+    let frame = 1.0 / 30.0;
+    // Alt+] at 4 s: the Out edge lands one frame after the playhead, so 4 s is the layer's last
+    // visible frame — it must not be cut away at the playhead (as in After Effects).
+    s.execute("time.set", json!({"time": 4.0})).unwrap();
+    s.execute("layer.timing", json!({"layers": [ids[0]], "op": "trimOutToTime"})).unwrap();
+    assert!((span(&s, ids[0]).1 - (4.0 + frame)).abs() < 1e-9, "{:?}", span(&s, ids[0]));
+    // Alt+[ at 2 s: the playhead's frame becomes the layer's first visible one.
+    s.execute("time.set", json!({"time": 2.0})).unwrap();
+    s.execute("layer.timing", json!({"layers": [ids[1]], "op": "trimInToTime"})).unwrap();
+    assert!((span(&s, ids[1]).0 - 2.0).abs() < 1e-9, "{:?}", span(&s, ids[1]));
+    // Trimmed before the In point, the Out point keeps one frame of layer.
+    s.execute("time.set", json!({"time": 0.5})).unwrap();
+    s.execute("layer.timing", json!({"layers": [ids[2]], "op": "trimOutToTime"})).unwrap();
+    assert!((span(&s, ids[2]).1 - (1.0 + frame)).abs() < 1e-9, "{:?}", span(&s, ids[2]));
+    // One undo step back to the original span.
+    assert!(s.undo());
+    assert!((span(&s, ids[2]).1 - 9.0).abs() < 1e-9);
+}
+
 #[test]
 fn masks_are_stepped_through_and_wrap() {
     let (mut s, ids) = session([(0.0, 10.0); 3]);
diff --git a/crates/engine/src/tests/stubs.rs b/crates/engine/src/tests/stubs.rs
index b36ad77be..9735f2c08 100644
--- a/crates/engine/src/tests/stubs.rs
+++ b/crates/engine/src/tests/stubs.rs
@@ -584,3 +584,22 @@ fn convert_to_bezier_reads_the_shape_as_it_is_set() {
     let mid = |v: &[f64]| (v.iter().copied().fold(f64::MAX, f64::min) + v.iter().copied().fold(f64::MIN, f64::max)) / 2.0;
     assert!((mid(&xs) - 10.0).abs() < 1e-6 && (mid(&ys) - 5.0).abs() < 1e-6, "centred on the position: {:?} {:?}", mid(&xs), mid(&ys));
 }
+
+/// #2201: a viewer drag on the free-transform box sends one `path.freeTransform` per frame with a
+/// shared merge key; one undo must revert the whole drag, not the last frame.
+#[test]
+fn free_transform_drag_undoes_in_one_step() {
+    let mut s = comp();
+    let (l, m) = masked(&mut s);
+    s.state.selected_vertices.clear();
+    let before = mask_path(&s, l, m);
+    for k in [90, 90, 90, 90] {
+        s.execute("path.freeTransform", json!({"layer": l, "scale": k, "merge": "viewer-drag-1"})).unwrap();
+    }
+    let after = mask_path(&s, l, m);
+    assert_ne!(after, before);
+    s.execute("edit.undo", json!({})).unwrap();
+    assert_eq!(mask_path(&s, l, m), before, "one undo reverts the whole drag");
+    s.execute("edit.redo", json!({})).unwrap();
+    assert_eq!(mask_path(&s, l, m), after, "redo restores the whole drag");
+}
diff --git a/crates/engine/src/tests/tail.rs b/crates/engine/src/tests/tail.rs
index 2710365eb..90cfd1bfc 100644
--- a/crates/engine/src/tests/tail.rs
+++ b/crates/engine/src/tests/tail.rs
@@ -421,6 +421,70 @@ fn camera_focus_commands_undo_and_serde() {
     assert!(s.execute("camera.linkFocusToPoi", json!({})).is_ok());
 }
 
+/// Set Focus Distance to Layer: degenerate targets (behind the camera, exactly at it) are clean
+/// errors, and a depth-of-field frame renders right after the command.
+#[test]
+fn camera_set_focus_to_layer_degenerate_targets_and_dof_frame() {
+    let mut s = comp(400, 300);
+    let t = s.execute("layer.newSolid", json!({"color": "#ffffff", "width": 50, "height": 50})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [t], "switch": "threeD", "value": true})).unwrap();
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("prop.set", json!({"layer": cam, "path": "transform/position", "value": [200, 150, -500]})).unwrap();
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/dof", "value": true})).unwrap();
+    s.execute("layer.select", json!({"layers": [cam, t]})).unwrap();
+    // Behind the camera (which now sits at z = −500 looking towards +z).
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, -1000]})).unwrap();
+    let e = s.execute("camera.setFocusToLayer", json!({})).unwrap_err().to_string();
+    assert!(e.contains("behind the camera"), "{e}");
+    // Exactly at the camera: depth 0, still a clean error.
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, -500]})).unwrap();
+    assert!(s.execute("camera.setFocusToLayer", json!({})).is_err());
+    // In front: the command works, and the depth-of-field frame renders with finite pixels.
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200, 150, 400]})).unwrap();
+    let d = s.execute("camera.setFocusToLayer", json!({})).unwrap()["focusDistance"].as_f64().unwrap();
+    assert!((d - 900.0).abs() < 1e-6, "{d}");
+    // An out-of-focus 3D layer, which must visibly blur, and a 0%-scaled one, whose pixels cover
+    // ~0 screen pixels and so turn an ordinary defocus into a radius of ~1e9 buffer pixels.
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/aperture", "value": 120})).unwrap();
+    let blur = s.execute("layer.newSolid", json!({"color": "#00ff00", "width": 60, "height": 60})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [blur], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": blur, "prop": "position", "value": [200, 150, 1200]})).unwrap();
+    let invis = s.execute("layer.newSolid", json!({"color": "#ff0000", "width": 40, "height": 40})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [invis], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": invis, "prop": "position", "value": [200, 150, 1600]})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": invis, "prop": "scale", "value": [0.0, 0.0, 0.0]})).unwrap();
+    let cid = s.active_comp_id().unwrap();
+    let img = s.render(cid, effectcraft_time::Tick::ZERO, Default::default());
+    assert!(img.data.iter().all(|p| p.iter().all(|c| c.is_finite())), "non-finite pixels after setFocusToLayer");
+    // The DoF frame actually blurred (not a no-op blur): the same frame with DoF off differs.
+    s.execute("prop.set", json!({"layer": cam, "path": "cameraOptions/dof", "value": false})).unwrap();
+    let plain = s.render(cid, effectcraft_time::Tick::ZERO, Default::default());
+    assert_ne!(img.data, plain.data, "the out-of-focus layer should have blurred");
+}
+
+/// Set Focus Distance to Layer fails cleanly on a depth that isn't finite. Every stored number
+/// here is finite, but their difference overflows f64 to infinity; JSON has no infinity, so
+/// storing it would leave a project that can't be saved.
+#[test]
+fn camera_set_focus_to_layer_rejects_non_finite_depth() {
+    let mut s = comp(400, 300);
+    let t = s.execute("layer.newSolid", json!({"color": "#ffffff", "width": 50, "height": 50})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [t], "switch": "threeD", "value": true})).unwrap();
+    s.execute("layer.setTransform", json!({"layer": t, "prop": "position", "value": [200.0, 150.0, 1e308]})).unwrap();
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("layer.setTransform", json!({"layer": cam, "prop": "position", "value": [200.0, 150.0, -1e308]})).unwrap();
+    s.execute("layer.select", json!({"layers": [cam, t]})).unwrap();
+    let before = s.execute("prop.get", json!({"layer": cam, "path": "cameraOptions/focusDistance"})).unwrap()["value"].as_f64().unwrap();
+    let e = s.execute("camera.setFocusToLayer", json!({})).unwrap_err().to_string();
+    assert!(e.contains("out of range"), "{e}");
+    let after = s.execute("prop.get", json!({"layer": cam, "path": "cameraOptions/focusDistance"})).unwrap()["value"].as_f64().unwrap();
+    assert!((after - before).abs() < 1e-9, "a non-finite focus distance was written: {after}");
+    // The project still round-trips through serde (a stored infinity would come back as null).
+    let back = roundtrip(&s);
+    let f = back.comp(s.active_comp_id().unwrap()).unwrap().layer(LayerId(cam)).unwrap().props.prop("cameraOptions/focusDistance").unwrap().value.as_f64();
+    assert!((f - before).abs() < 1e-9, "serde focus distance: {f}");
+}
+
 /// An id sent as a string (`"98"`, as MCP clients often do) resolves as an id when no name matches.
 #[test]
 fn numeric_string_resolves_as_id() {
diff --git a/crates/engine/src/tests/text_edit.rs b/crates/engine/src/tests/text_edit.rs
index 17d0345d8..7a04ea155 100644
--- a/crates/engine/src/tests/text_edit.rs
+++ b/crates/engine/src/tests/text_edit.rs
@@ -199,6 +199,20 @@ fn typing_deleting_and_caret_movement() {
     assert!(s.state.text_edit.is_none());
 }
 
+/// Duplicating during a text edit moves the selection to the copy: the edit on the original ends
+/// (#2226), as in After Effects — typing must not keep editing an unselected layer.
+#[test]
+fn duplicate_during_a_text_edit_ends_the_edit() {
+    let (mut s, t) = session("Hello");
+    s.execute("text.edit", json!({"layer": t, "caret": 5})).unwrap();
+    let copy = s.execute("edit.duplicate", json!({"layers": [t]})).unwrap()[0].as_u64().unwrap();
+    assert_ne!(copy, t, "the duplicate is created");
+    assert_eq!(s.state.selected_layers, vec![effectcraft_project::LayerId(copy)], "the copy is selected");
+    assert!(s.state.text_edit.is_none(), "the edit ended with the selection move (#2226)");
+    assert_eq!(doc(&s, t).text, "Hello", "the original keeps its text");
+    assert_eq!(doc(&s, copy).text, "Hello", "and the copy carries it");
+}
+
 #[test]
 fn caret_style_applies_to_the_next_typed_text() {
     let (mut s, t) = session("ab");
@@ -260,25 +274,25 @@ fn clipboard_and_paste_formatting() {
 }
 
 #[test]
-fn type_tool_layers_point_box_and_empty_cleanup() {
+fn type_tool_layers_point_box_and_empty_layer_is_kept() {
     let mut s = Session::default();
     s.execute("comp.new", json!({"name": "C", "width": 640, "height": 360, "duration": 4})).unwrap();
     let t = s.execute("layer.newText", json!({"text": "", "position": [100, 200], "justify": "left", "edit": true})).unwrap()["layer"].as_u64().unwrap();
     assert_eq!(s.state.text_edit.as_ref().map(|e| e.layer.0), Some(t));
-    // Leaving an untouched Type-tool layer deletes it.
+    // Leaving an untouched Type-tool layer keeps it, as After Effects does.
     s.execute("text.endEdit", json!({})).unwrap();
-    assert!(s.active_comp().unwrap().layers.is_empty());
+    assert_eq!(s.active_comp().unwrap().layers.len(), 1, "an empty Type-tool layer is kept, as in AE");
     let b = s.execute("layer.newText", json!({"text": "", "box": [40, 50, 300, 120], "edit": true})).unwrap()["layer"].as_u64().unwrap();
     s.execute("text.insert", json!({"text": "Boxed"})).unwrap();
     let d = doc(&s, b);
     assert_eq!(d.box_size, Some([300.0, 120.0]));
     assert_eq!(d.box_pos, [-150.0, -60.0]);
-    let l = s.active_comp().unwrap().layers[0].clone();
+    let l = s.active_comp().unwrap().layers.iter().find(|l| l.id.0 == b).expect("the boxed layer").clone();
     assert_eq!(l.name, "Boxed", "named after its text");
     let pos = l.props.prop("transform/position").unwrap().value.as_vec3();
     assert_eq!([pos[0], pos[1]], [190.0, 110.0]);
     s.execute("text.endEdit", json!({})).unwrap();
-    assert_eq!(s.active_comp().unwrap().layers.len(), 1);
+    assert_eq!(s.active_comp().unwrap().layers.len(), 2, "both text layers stay, the empty one included");
     // Resizing the box (layer space) is an attribute too.
     s.execute("layer.setText", json!({"layer": b, "box": [-100, -60, 200, 120]})).unwrap();
     assert_eq!(doc(&s, b).box_size, Some([200.0, 120.0]));
@@ -928,11 +942,19 @@ fn fonts_lists_bundled_and_installed_families() {
     let r = s.execute("text.fonts", json!({"query": "noto ser", "rescan": true})).unwrap();
     assert_eq!(r["families"][0]["family"], "Noto Serif");
     // The bundled face is Regular; the OS can also provide Bold, Italic, or other faces.
-    // Compare against the independent directory inventory rather than assuming an empty OS.
-    let mut expected_styles = std::collections::BTreeSet::from(["Regular".to_string()]);
-    expected_styles.extend(installed.iter().filter(|face| face.family.eq_ignore_ascii_case("Noto Serif")).map(|face| face.style.clone()));
+    // Model `add_source()` on the independent directory inventory: a system face whose family
+    // and primary style duplicate an earlier face is skipped, with its named instances.
+    let mut expected_styles = std::collections::BTreeSet::from(["regular".to_string()]);
+    let mut retained = std::collections::BTreeSet::from([("noto serif".to_string(), "regular".to_string())]);
+    for face in installed.iter().filter(|face| face.family.eq_ignore_ascii_case("Noto Serif")) {
+        if retained.insert((face.family.to_ascii_lowercase(), face.style.to_ascii_lowercase())) {
+            expected_styles.insert(face.style.to_ascii_lowercase());
+            expected_styles.extend(face.instances.iter().map(|i| i.style.to_ascii_lowercase()));
+        }
+    }
     let styles: Vec<String> = r["families"][0]["styles"].as_array().unwrap().iter().map(|style| style.as_str().unwrap().to_string()).collect();
-    assert_eq!(styles.iter().cloned().collect::<std::collections::BTreeSet<_>>(), expected_styles);
+    // `families()` keeps the first spelling of a style that differs only in case.
+    assert_eq!(styles.iter().map(|style| style.to_ascii_lowercase()).collect::<std::collections::BTreeSet<_>>(), expected_styles);
     assert_eq!(styles.len(), expected_styles.len(), "style menu has no duplicates");
     assert!(r["families"].as_array().unwrap().iter().all(|f| f["family"].as_str().unwrap().to_lowercase().contains("noto ser")));
     // The style menus offer a family's own styles.
@@ -1202,7 +1224,7 @@ fn deselect_all_ends_the_open_edit() {
 }
 
 #[test]
-fn deselect_all_discards_an_empty_type_tool_layer() {
+fn deselect_all_keeps_an_empty_type_tool_layer() {
     let (mut s, _keep) = session("Hello");
     let new = s.execute("layer.newText", json!({"text": "", "position": [80.0, 80.0], "edit": true})).unwrap()["layer"].as_u64().unwrap();
     assert!(
@@ -1214,7 +1236,5 @@ fn deselect_all_discards_an_empty_type_tool_layer() {
     s.execute("edit.deselectAll", json!({})).unwrap();
     assert!(s.state.text_edit.is_none());
     assert!(s.state.selected_layers.is_empty());
-    assert_eq!(count(&s), before - 1, "a Type-tool layer left empty is removed, as text.endEdit does");
-    s.execute("edit.undo", json!({})).unwrap();
-    assert_eq!(count(&s), before, "that removal is one undo step of its own, as on text.endEdit");
+    assert_eq!(count(&s), before, "an empty Type-tool layer is kept, as in After Effects");
 }
diff --git a/crates/engine/src/tests/viewer.rs b/crates/engine/src/tests/viewer.rs
index 5ed0848b9..1ff12237e 100644
--- a/crates/engine/src/tests/viewer.rs
+++ b/crates/engine/src/tests/viewer.rs
@@ -419,7 +419,7 @@ fn shape_tool_options_paint_new_shapes() {
 fn masks_of_every_shape_tool_kind() {
     let mut s = comp();
     let sol = s.execute("layer.newSolid", json!({"color": "#ffffff"})).unwrap()["layer"].as_u64().unwrap();
-    for (kind, n) in [("rect", 4), ("ellipse", 4), ("rounded", 8), ("polygon", 6), ("star", 10)] {
+    for (kind, n) in [("rect", 4), ("ellipse", 4), ("rounded", 8), ("polygon", 5), ("star", 10)] {
         let m = s.execute("layer.addMask", json!({"layer": sol, "shape": kind, "rect": [100, 100, 80, 80]})).unwrap()["mask"].as_u64().unwrap();
         let path = layer(&s, sol).props.find_group(m).unwrap().get("path").unwrap().value.as_path().unwrap().clone();
         assert!(path.closed, "{kind}");
diff --git a/crates/engine/tests/it/parenting_3d_position.rs b/crates/engine/tests/it/parenting_3d_position.rs
index f9dd9ae3f..61440e273 100644
--- a/crates/engine/tests/it/parenting_3d_position.rs
+++ b/crates/engine/tests/it/parenting_3d_position.rs
@@ -410,12 +410,12 @@ fn parenting_static_orientation_is_exact_just_off_gimbal_lock() {
 fn parenting_animated_orientation_and_nonuniform_parent_keep_authored_pose_boundary() {
     for animated in [true, false] {
         let (mut s, p, c) = fixture(true, true);
+        // A non-uniform parent has no uniform pose to re-express, animated or not.
+        set(&mut s, p, "transform/scale", json!([120.0, 100.0, 80.0]));
         if animated {
             for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
                 command(&mut s, "prop.addKey", json!({"layer":c,"path":"transform/orientation","time":time,"value":value}));
             }
-        } else {
-            set(&mut s, p, "transform/scale", json!([120.0, 100.0, 80.0]));
         }
         let layer = s.active_comp().unwrap().layer(LayerId(c)).unwrap();
         let orientation = layer.props.prop("transform/orientation").unwrap().clone();
@@ -430,6 +430,27 @@ fn parenting_animated_orientation_and_nonuniform_parent_keep_authored_pose_bound
     }
 }
 
+/// Keyed Orientation under a uniform parent is re-expressed at every key, so the child's world pose
+/// and pixels stay put at every time (the parent is Z-only, so the paths between keys stay exact too).
+#[test]
+fn parenting_uniform_parent_re_expresses_keyed_orientation() {
+    for factor in [120.0, -120.0] {
+        let (mut s, p, c) = fixture(true, false);
+        set(&mut s, p, "transform/rotation", json!(42.0));
+        set(&mut s, p, "transform/scale", json!([factor, factor, factor]));
+        for (time, value) in [(0.0, json!([-8.0, 12.0, -13.0])), (1.0, json!([5.0, 18.0, 14.0]))] {
+            command(&mut s, "prop.addKey", json!({"layer":c,"path":"transform/orientation","time":time,"value":value}));
+        }
+        let times = [0.0, 0.25, 0.5, 0.75, 1.0].map(Tick::from_seconds_f64);
+        let before = times.map(|t| world(&s, c, t));
+        let images = times.map(|t| cpu(&s, t));
+        parent(&mut s, c, Some(p), true);
+        let error = times.into_iter().zip(before).map(|(t, b)| displacement(b, world(&s, c, t))).fold(0.0, f64::max);
+        let pixels = times.into_iter().zip(&images).map(|(t, i)| diff(i, &cpu(&s, t))).fold(0.0, f32::max);
+        assert!(error < 1e-8 && pixels < 2e-5, "keyed Orientation under a uniform parent (factor {factor}): corners {error}, pixels {pixels}");
+    }
+}
+
 /// Position's temporal speed is measured along its spatial path, in parent-space units.
 #[test]
 fn parenting_uniform_parent_preserves_eased_position_at_quarter_times_and_undo() {
diff --git a/crates/export/src/lib.rs b/crates/export/src/lib.rs
index fd1ace60b..1b69a87bd 100644
--- a/crates/export/src/lib.rs
+++ b/crates/export/src/lib.rs
@@ -376,7 +376,7 @@ async fn gif_export(job: &Cx<'_>, comp: &Comp, w: u32, h: u32, st: &mut State<'_
         let end = (i + batch).min(st.total);
         let frames: Vec<gif::Frame<'static>> = job
             .frames(comp, (i..end).collect(), |_, img| {
-                let mut px = job.pixels(&img, comp, job.output.channels, w, h);
+                let mut px = job.pixels_with(&img, comp, job.output.channels, w, h, false);
                 gif::Frame::from_rgba_speed(w as u16, h as u16, &mut px, 10)
             })
             .await;
diff --git a/crates/export/src/pipeline.rs b/crates/export/src/pipeline.rs
index b185c3345..c639ebad1 100644
--- a/crates/export/src/pipeline.rs
+++ b/crates/export/src/pipeline.rs
@@ -4,10 +4,8 @@
 
 use std::sync::Mutex;
 
-use effectcraft_project::render_queue::{
-    AlphaMode, Channels, ColorDepth, CurrentOrOff, EffectsMode, FrameSample, RenderLog, ResizeQuality, SwitchOverride, log_path,
-};
-use effectcraft_project::{Comp, Project};
+use effectcraft_project::render_queue::{AlphaMode, Channels, CurrentOrOff, EffectsMode, FrameSample, RenderLog, ResizeQuality, SwitchOverride, log_path};
+use effectcraft_project::{BitDepth, Comp, Project};
 use effectcraft_raster::Image;
 use effectcraft_render::{Backend, LayerCache, RenderOpts, Renderer};
 use effectcraft_time::Tick;
@@ -220,6 +218,9 @@ impl<'a> Cx<'a> {
     pub fn new(job: &'a Job<'a>) -> Cx<'a> {
         let mut project = job.project.clone();
         apply_overrides(&mut project, job);
+        // Render Settings ▸ Color Depth overrides the project's depth for the whole render (every
+        // layer and effect quantises at it), not just the finished frame (#2022).
+        project.settings.bit_depth = job.settings.color_depth.resolve(project.settings.bit_depth);
         let frame_times = (job.options.log == RenderLog::PlusPerFrameInfo).then(|| Mutex::new(Vec::new()));
         let cache = LayerCache::default();
         // With deferred readbacks, buffers computed from a missed pass's placeholders are not kept.
@@ -240,7 +241,7 @@ impl<'a> Cx<'a> {
         // compositors differ slightly, so a per-frame choice made renders differ run to run.
         let backend = if self.project.settings.gpu_acceleration { Backend::Gpu } else { Backend::Cpu };
         let opts = RenderOpts {
-            scale: s.resolution.clamp(0.01, 4.0),
+            scale: self.comp().map(|c| s.effective_scale(c)).unwrap_or_else(|| s.resolution.clamp(0.01, 4.0)),
             motion_blur: s.motion_blur_override() != SwitchOverride::OffForAll,
             guides: s.guide_layers == CurrentOrOff::Current,
             draft: s.quality == RenderQuality::Draft,
@@ -360,14 +361,6 @@ impl<'a> Cx<'a> {
                 if second == first { a } else { interleave(&a, &self.render_at(second).await, upper_first) }
             }
         };
-        let mut img = img;
-        // Color Depth: renders run at the project's depth; another depth quantises the frame.
-        let depth = self.job.settings.color_depth;
-        if depth != ColorDepth::Current
-            && let Some(levels) = depth.resolve(self.project.settings.bit_depth).levels()
-        {
-            img.quantize(levels);
-        }
         let img = self.crop_resize(img);
         if let Some(ft) = &self.frame_times {
             ft.lock().unwrap_or_else(std::sync::PoisonError::into_inner).push((i, t0.elapsed().as_secs_f64()));
@@ -384,12 +377,14 @@ impl<'a> Cx<'a> {
             return None;
         }
         let FrameSample::Progressive(t) = self.job.settings.sample(comp, i) else { return None };
-        let depth = self.job.settings.color_depth;
-        if depth != ColorDepth::Current && depth.resolve(self.project.settings.bit_depth).levels().is_some() {
+        // Above 8 bpc the colour is dithered on its way to 8 bits (`Cx::pixels`), which the
+        // accelerator's conversion doesn't do: those frames render as usual so H.264 doesn't
+        // band (#2022). The project's depth already includes Render Settings ▸ Color Depth.
+        if self.project.settings.bit_depth != BitDepth::Bpc8 {
             return None;
         }
         let om = self.job.output;
-        let scale = self.job.settings.resolution.clamp(0.01, 4.0);
+        let scale = self.job.settings.effective_scale(comp);
         let size = |n: u32| ((n as f64 * scale).round() as u32).max(1);
         if om.resize.enabled || (size(comp.width), size(comp.height)) != (w, h) || om.crop.edges(w, h, scale) != (0, 0, 0, 0) {
             return None;
@@ -435,7 +430,7 @@ impl<'a> Cx<'a> {
     /// Output Module ▸ Crop, then Resize.
     fn crop_resize(&self, img: Image) -> Image {
         let om = self.job.output;
-        let scale = self.job.settings.resolution.clamp(0.01, 4.0);
+        let scale = self.comp().map(|c| self.job.settings.effective_scale(c)).unwrap_or_else(|| self.job.settings.resolution.clamp(0.01, 4.0));
         let (t, l, b, r) = om.crop.edges(img.width, img.height, scale);
         let img = if (t, l, b, r) == (0, 0, 0, 0) { img } else { crop(&img, t, l, b, r) };
         if !om.resize.enabled {
@@ -453,12 +448,24 @@ impl<'a> Cx<'a> {
 
     /// 8-bit RGBA of the requested channels cropped/padded to `w`×`h` (codec rounding): RGB over
     /// the comp background (opaque), RGB + Alpha straight or premultiplied, or the alpha matte.
+    /// When the render runs above 8 bpc, the colour is dithered on its way to 8 bits, as After
+    /// Effects dithers colours converted down to 8 bpc for rendering and export, so gradients
+    /// rendered at 16 or 32 bpc don't band (#2022). An 8 bpc render has no finer values to
+    /// dither, so its output stays byte for byte what it was.
     pub fn pixels(&self, img: &Image, comp: &Comp, channels: Channels, w: u32, h: u32) -> Vec<u8> {
+        let dither = self.project.settings.bit_depth != BitDepth::Bpc8;
+        self.pixels_with(img, comp, channels, w, h, dither)
+    }
+
+    /// [`Cx::pixels`], dithering the colour or not (a GIF palette gains nothing from dither noise).
+    pub fn pixels_with(&self, img: &Image, comp: &Comp, channels: Channels, w: u32, h: u32, dither: bool) -> Vec<u8> {
         let px = match channels {
+            Channels::Rgb if dither => img.to_rgba8_over_dithered(comp.background),
             Channels::Rgb => img.to_rgba8_over(comp.background),
-            Channels::Rgba => match self.job.output.alpha_mode {
-                AlphaMode::Straight => img.to_rgba8(),
-                AlphaMode::Premultiplied => premultiplied8(img),
+            Channels::Rgba => match (self.job.output.alpha_mode, dither) {
+                (AlphaMode::Straight, true) => img.to_rgba8_dithered(),
+                (AlphaMode::Straight, false) => img.to_rgba8(),
+                (AlphaMode::Premultiplied, _) => premultiplied8(img, dither),
             },
             Channels::Alpha => img
                 .data
@@ -619,15 +626,22 @@ fn bicubic(src: &Image, w: u32, h: u32) -> Image {
     out
 }
 
-/// Premultiplied 8-bit RGBA (colour matted with black).
-fn premultiplied8(img: &Image) -> Vec<u8> {
-    img.data
-        .iter()
-        .flat_map(|p| {
-            let a = p[3].clamp(0.0, 1.0);
-            [0, 1, 2].map(|c| (p[c].clamp(0.0, a) * 255.0 + 0.5) as u8).into_iter().chain([(a * 255.0 + 0.5) as u8])
-        })
-        .collect()
+/// Premultiplied 8-bit RGBA (colour matted with black), the colour dithered when `dither`.
+fn premultiplied8(img: &Image, dither: bool) -> Vec<u8> {
+    let w = img.width.max(1) as usize;
+    let mut out = Vec::with_capacity(img.data.len() * 4);
+    for (i, p) in img.data.iter().enumerate() {
+        let a = p[3].clamp(0.0, 1.0);
+        let a8 = (a * 255.0 + 0.5) as u8;
+        let (x, y) = ((i % w) as u32, (i / w) as u32);
+        for c in 0..3 {
+            let v = p[c].clamp(0.0, a);
+            // Dither may round up past the rounded alpha; premultiplied colour never exceeds it.
+            out.push(if dither { effectcraft_raster::dither_u8(v, x, y).min(a8) } else { (v * 255.0 + 0.5) as u8 });
+        }
+        out.push(a8);
+    }
+    out
 }
 
 #[cfg(test)]
@@ -636,6 +650,19 @@ mod tests {
     use rayon::prelude::*;
     use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 
+    /// Dither may round a colour up while alpha rounds down; premultiplied colour stays at or
+    /// below the written alpha at every pixel.
+    #[test]
+    fn dithered_premultiplied_colour_never_exceeds_alpha() {
+        let v = 100.25 / 255.0;
+        let img = Image::filled(64, 64, [v, v, v, v]);
+        let px = premultiplied8(&img, true);
+        assert!(px.as_chunks::<4>().0.iter().all(|p| p[..3].iter().all(|c| *c <= p[3])), "a colour byte is above its alpha");
+        assert!(px.as_chunks::<4>().0.iter().all(|p| p[3] == 100));
+        let plain = premultiplied8(&img, false);
+        assert!(plain.as_chunks::<4>().0.iter().all(|p| *p == [100, 100, 100, 100]));
+    }
+
     /// Frames `0..n` through [`map_frames`] with `cap`, recording the most running at once.
     fn run_capped(n: u64, cap: Option<usize>) -> (Vec<u64>, usize) {
         use std::sync::atomic::{AtomicUsize, Ordering};
diff --git a/crates/export/tests/it/banding.rs b/crates/export/tests/it/banding.rs
new file mode 100644
index 000000000..3f99f1eb6
--- /dev/null
+++ b/crates/export/tests/it/banding.rs
@@ -0,0 +1,156 @@
+//! Gradients exported at 16 bpc (or with a 16 bpc Color Depth override) don't band (#2022): the
+//! float frame is dithered on its way to 8 bits, and the Render Settings' Color Depth reaches the
+//! render itself.
+
+use std::sync::{Arc, Mutex};
+
+use effectcraft_color::Label;
+use effectcraft_export::render_queue::*;
+use effectcraft_export::{Job, JobOptions, Sink, export};
+use effectcraft_keyframe::Value;
+use effectcraft_project::build::{self, Ids};
+use effectcraft_project::{BitDepth, Comp, ItemId, ItemKind, LayerSource, Project, Solid};
+use effectcraft_render::NoFootage;
+use effectcraft_time::{FrameRate, Tick};
+
+const W: u32 = 1024;
+const H: u32 = 16;
+/// The ramp runs from this grey to `HI` across the comp: about 25 eight-bit codes in 1024 px,
+/// so plain rounding makes bands about 40 px wide.
+const LO: f64 = 0.20;
+const HI: f64 = 0.30;
+/// Width of the column blocks whose mean is compared with the ideal ramp.
+const WINDOW: u32 = 8;
+
+/// A grey horizontal ramp over a comp of the given project depth.
+fn ramp_project(depth: BitDepth) -> (Project, ItemId) {
+    let mut p = Project::default();
+    p.settings.bit_depth = depth;
+    let mut comp = Comp::new(W, H, FrameRate::new(25, 1), Tick::from_seconds_f64(1.0));
+    comp.background = [0.0, 0.0, 0.0];
+    let sid = p.add_item("Ramp", Label::Red, None, ItemKind::Solid(Solid { color: [1.0, 1.0, 1.0], width: W, height: H, pixel_aspect: 1.0 }));
+    let mut layer = build::layer(&mut p, &comp, "Ramp", LayerSource::Solid { item: sid }, (W, H), None);
+    let spec = effectcraft_effects::find("ec.generate.gradientramp").expect("gradient ramp effect");
+    let mut next = p.next_id;
+    let mut group = effectcraft_effects::instantiate(spec, &mut Ids(&mut next), spec.name, [W as f64, H as f64]);
+    p.next_id = next;
+    for (k, v) in [
+        ("start", Value::Vec2([0.0, 0.0])),
+        ("end", Value::Vec2([W as f64, 0.0])),
+        ("startColor", Value::Color([LO, LO, LO, 1.0])),
+        ("endColor", Value::Color([HI, HI, HI, 1.0])),
+    ] {
+        group.get_mut(k).expect("ramp parameter").value = v;
+    }
+    layer.props.sub_mut("effects").expect("effects group").children.push(group.into());
+    comp.layers.push(layer);
+    let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(comp.into()));
+    (p, cid)
+}
+
+/// Export frame 0 as PNG with the Render Settings' Color Depth `depth` and return the grey of
+/// every row.
+fn export_rows(p: &Project, cid: ItemId, depth: ColorDepth) -> Vec<Vec<u8>> {
+    let files: Arc<Mutex<Vec<(String, Vec<u8>)>>> = Default::default();
+    let f = files.clone();
+    let sink: Box<Sink> = Box::new(move |path: &str, data: Vec<u8>| f.lock().unwrap().push((path.to_string(), data)));
+    let settings =
+        RenderSettings { time_span: TimeSpan::Custom { start: Tick::ZERO, end: Tick::from_seconds_f64(0.04) }, color_depth: depth, ..Default::default() };
+    let om = OutputModule::for_format(OutputFormat::PngSequence);
+    let job = Job {
+        project: p,
+        footage: &NoFootage,
+        expr: None,
+        accel: None,
+        comp: cid,
+        settings: &settings,
+        output: &om,
+        path: "/banding/f_[#####].png",
+        sink: Some(&*sink),
+        options: JobOptions::default(),
+        nested_switches: true,
+    };
+    export(&job, &mut |_| true).expect("export");
+    let files = files.lock().unwrap();
+    let (_, png) = files.iter().find(|(path, _)| path.ends_with(".png")).expect("a PNG");
+    let img = image::load_from_memory(png).expect("png").to_rgba8();
+    (0..H).map(|y| (0..W).map(|x| img.get_pixel(x, y).0[1]).collect()).collect()
+}
+
+/// The ideal ramp at column `x`, in 8-bit codes.
+fn ideal(x: f64) -> f64 {
+    255.0 * (LO + (HI - LO) * (x + 0.5) / W as f64)
+}
+
+/// Longest run of equal neighbours in the row: a band's width.
+fn longest_run(row: &[u8]) -> usize {
+    let (mut best, mut run) = (1, 1);
+    for w in row.windows(2) {
+        run = if w[0] == w[1] { run + 1 } else { 1 };
+        best = best.max(run);
+    }
+    best
+}
+
+/// Horizontal neighbours with different values, over all rows: ~25 per row when every band is a
+/// flat step, hundreds when the steps are dithered.
+fn transitions(rows: &[Vec<u8>]) -> usize {
+    rows.iter().map(|r| r.windows(2).filter(|w| w[0] != w[1]).count()).sum()
+}
+
+/// Largest difference, in 8-bit codes, between the mean of a `WINDOW`-column block over all rows
+/// and the ideal ramp's mean over it. Plain rounding leaves up to ~0.4 codes of it beside a step
+/// edge; dither averages it away (its noise on a mean of `WINDOW * H` samples is under 0.05).
+fn worst_window_error(rows: &[Vec<u8>]) -> f64 {
+    (0..W / WINDOW)
+        .map(|i| {
+            let (x0, x1) = ((i * WINDOW) as usize, ((i + 1) * WINDOW) as usize);
+            let sum: f64 = rows.iter().flat_map(|r| &r[x0..x1]).map(|&v| v as f64).sum();
+            let mean = sum / (rows.len() * (x1 - x0)) as f64;
+            (mean - ideal((x0 + x1) as f64 / 2.0 - 1.0)).abs()
+        })
+        .fold(0.0, f64::max)
+}
+
+#[test]
+fn a_16_bpc_gradient_export_is_dithered() {
+    let (p, cid) = ramp_project(BitDepth::Bpc16);
+    let rows = export_rows(&p, cid, ColorDepth::Current);
+    let (steps, err) = (transitions(&rows), worst_window_error(&rows));
+    eprintln!("16 bpc project: {steps} transitions, worst {WINDOW}-px mean error {err:.3} codes");
+    // Undithered there are ~25 flat steps per row (400 transitions) and the block means are off
+    // by up to ~0.4 codes.
+    assert!(steps > 2000, "the steps survive: {steps} transitions");
+    assert!(err < 0.25, "the local mean is off by {err} codes");
+    // Dither never moves a value a whole code from the ideal ramp.
+    for row in &rows {
+        for (x, &v) in row.iter().enumerate() {
+            let want = ideal(x as f64);
+            assert!((v as f64 - want).abs() < 1.05, "x {x}: {v} vs {want}");
+        }
+    }
+}
+
+#[test]
+fn the_export_is_the_same_every_time() {
+    let (p, cid) = ramp_project(BitDepth::Bpc16);
+    assert_eq!(export_rows(&p, cid, ColorDepth::Current), export_rows(&p, cid, ColorDepth::Current));
+}
+
+#[test]
+fn the_render_color_depth_reaches_the_render() {
+    // An 8 bpc project renders every layer at 8 bits: flat steps, nothing for the output to dither.
+    let (p, cid) = ramp_project(BitDepth::Bpc8);
+    let banded = export_rows(&p, cid, ColorDepth::Current);
+    assert!(longest_run(&banded[0]) >= 30, "an 8 bpc render is quantised before export");
+    assert!(transitions(&banded) < 16 * 30);
+    // The Render Settings' 16 bpc depth overrides the project's: the render keeps its precision
+    // until the final conversion, which dithers.
+    let deep = export_rows(&p, cid, ColorDepth::Bpc16);
+    let (steps, err) = (transitions(&deep), worst_window_error(&deep));
+    eprintln!("8 bpc project, 16 bpc render: {steps} transitions, worst {WINDOW}-px mean error {err:.3} codes");
+    assert!(steps > 2000 && err < 0.25, "a 16 bpc render still bands: {steps} transitions, error {err}");
+    // And 8 bpc on a 16 bpc project renders at 8 bits.
+    let (p16, cid16) = ramp_project(BitDepth::Bpc16);
+    assert_eq!(export_rows(&p16, cid16, ColorDepth::Bpc8), banded);
+}
diff --git a/crates/export/tests/it/h264_gpu_yuv.rs b/crates/export/tests/it/h264_gpu_yuv.rs
index 59e670779..0f99a7b54 100644
--- a/crates/export/tests/it/h264_gpu_yuv.rs
+++ b/crates/export/tests/it/h264_gpu_yuv.rs
@@ -6,7 +6,7 @@ use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 use effectcraft_color::Label;
-use effectcraft_export::render_queue::{OutputFormat, OutputModule, RenderSettings, TimeSpan};
+use effectcraft_export::render_queue::{ColorDepth, OutputFormat, OutputModule, RenderSettings, TimeSpan};
 use effectcraft_export::{Job, export};
 use effectcraft_project::{Comp, ItemId, ItemKind, LayerSource, Project, Solid, build};
 use effectcraft_raster::Image;
@@ -147,6 +147,20 @@ fn frames_the_accelerator_cannot_take_fall_back_to_rgba() {
     assert!(a == c);
 }
 
+/// Above 8 bpc the colour is dithered on its way to 8 bits, which the accelerator's planes
+/// don't do: those frames take the RGBA path, so an H.264 export doesn't band (#2022).
+#[test]
+fn renders_above_8_bpc_skip_the_planes() {
+    let d = out_dir("h264-gpu-yuv-16bpc");
+    let (p, cid) = project();
+    let s = RenderSettings { time_span: TimeSpan::LengthOfComp, color_depth: ColorDepth::Bpc16, ..Default::default() };
+    let yuv = Fake::new(true, false, usize::MAX);
+    let a = run(&p, cid, Some(&yuv), &s, &d.join("yuv.mp4"));
+    let c = run(&p, cid, None, &s, &d.join("cpu.mp4"));
+    assert_eq!(yuv.yuv_frames.load(Ordering::SeqCst), 0, "no planes asked for above 8 bpc");
+    assert!(a == c);
+}
+
 /// With deferred readbacks the export keeps rendering frames in passes (`Cx::frames`), never
 /// through the blocking per-frame path the planes use.
 #[test]
diff --git a/crates/export/tests/it/main.rs b/crates/export/tests/it/main.rs
index 0064ba8b7..88398a0e8 100644
--- a/crates/export/tests/it/main.rs
+++ b/crates/export/tests/it/main.rs
@@ -1,6 +1,7 @@
 //! The crate's integration tests, one binary (each module is a former `tests/<name>.rs`).
 
 mod audio_sample_positions;
+mod banding;
 mod h264_gpu_yuv;
 mod hevc_av1_roundtrip;
 #[cfg(not(target_arch = "wasm32"))]
diff --git a/crates/expr/src/host.rs b/crates/expr/src/host.rs
index a25fbc4f0..fa2993f97 100644
--- a/crates/expr/src/host.rs
+++ b/crates/expr/src/host.rs
@@ -10,7 +10,7 @@
 use effectcraft_geom::{Mat3, Mat4};
 use effectcraft_keyframe::Value;
 use effectcraft_project::{Comp, ItemId, ItemKind, Layer, LayerId, LayerSource, Node, PropGroup, Property};
-use effectcraft_render::{EvalCtx, source_size};
+use effectcraft_render::EvalCtx;
 use effectcraft_time::Tick;
 
 /// A name-or-index argument (`layer("A")`, `layer(2)`, `effect(1)`).
@@ -299,7 +299,17 @@ impl<'a> Resolver<'a> {
     }
     fn ctx_at(&self, c: u64, t: f64) -> Option<EvalCtx<'a>> {
         let comp = self.comp(c)?;
-        Some(EvalCtx { project: self.ctx.project, comp_id: ItemId(c), comp, time: Tick::from_seconds_f64(t), expr: self.ctx.expr, footage: self.ctx.footage })
+        let same_comp = c == self.ctx.comp_id.0;
+        Some(EvalCtx {
+            project: self.ctx.project,
+            comp_id: ItemId(c),
+            comp,
+            time: Tick::from_seconds_f64(t),
+            expr: self.ctx.expr,
+            footage: self.ctx.footage,
+            property_overrides: if same_comp { self.ctx.property_overrides } else { &[] },
+            media_overrides: if same_comp { self.ctx.media_overrides } else { &[] },
+        })
     }
     fn prop(&self, c: u64, l: u64, path: &str) -> Option<(&'a Layer, &'a Property)> {
         let layer = self.layer(c, l)?;
@@ -372,7 +382,7 @@ impl<'a> Resolver<'a> {
             Req::LayerInfo { comp, layer } => {
                 let c = self.comp(*comp)?;
                 let l = self.layer(*comp, *layer)?;
-                let (mut w, mut h) = source_size(project, l);
+                let (mut w, mut h) = self.ctx_at(*comp, self.ctx.time.seconds())?.source_size(l);
                 if w == 0 || h == 0 {
                     (w, h) = (c.width, c.height);
                 }
@@ -467,7 +477,7 @@ impl<'a> Resolver<'a> {
                         }
                     }
                     _ => {
-                        let (w, h) = source_size(project, l);
+                        let (w, h) = ctx.source_size(l);
                         [0.0, 0.0, w as f64, h as f64]
                     }
                 };
@@ -501,7 +511,12 @@ impl<'a> Resolver<'a> {
             Req::SourceInfo { comp, layer } => {
                 let c = self.comp(*comp)?;
                 let l = self.layer(*comp, *layer)?;
-                let it = project.item(l.source.item()?)?;
+                let ctx = self.ctx_at(*comp, self.ctx.time.seconds())?;
+                let item = match &l.source {
+                    LayerSource::Footage { item } => ctx.media_item(l, *item),
+                    _ => l.source.item()?,
+                };
+                let it = project.item(item)?;
                 let (kind, aspect, frame, duration) = match &it.kind {
                     ItemKind::Comp(nc) => ("comp", nc.pixel_aspect, nc.frame_duration().seconds(), nc.duration.seconds()),
                     ItemKind::Footage(f) => ("footage", f.pixel_aspect, f.frame_rate.frame_duration().seconds(), f.duration.seconds()),
diff --git a/crates/expr/src/lib.rs b/crates/expr/src/lib.rs
index c77af5b37..9e78d250f 100644
--- a/crates/expr/src/lib.rs
+++ b/crates/expr/src/lib.rs
@@ -17,7 +17,8 @@
 //!   `sourceRectAtTime`), property methods (`valueAtTime`, `velocityAtTime`, `speedAtTime`, `key`,
 //!   `nearestKey`, `numKeys`, `wiggle`, `temporalWiggle`, `smooth`, `loopIn/Out[Duration]`) and the
 //!   global helpers (`linear`/`ease`/`easeIn`/`easeOut`, `random`/`gaussRandom`/`seedRandom`/
-//!   `noise`, vector maths, `clamp`, `lookAt`, time and colour conversions, `posterizeTime`).
+//!   `noise`, vector maths, `clamp`, `lookAt`, time and colour conversions, `posterizeTime`),
+//!   plus `bezier`, a CSS-style cubic-Bezier easing helper that After Effects does not have.
 //! * **Determinism**: `wiggle` and `random` are seeded by layer index, property uid (and time /
 //!   `seedRandom`), so frames render identically on every thread and platform.
 //! * **Runtime**: one boa `Context` per thread with compiled scripts cached by text. Scripts read
@@ -162,7 +163,16 @@ fn evaluate_out(
         return Err("Error: expressions reference each other too deeply (circular reference?)".into());
     }
     budget_left()?;
-    let ctx = EvalCtx { project: ctx.project, comp_id: ctx.comp_id, comp: ctx.comp, time: ctx.time, expr: Some(host), footage: ctx.footage };
+    let ctx = EvalCtx {
+        project: ctx.project,
+        comp_id: ctx.comp_id,
+        comp: ctx.comp,
+        time: ctx.time,
+        expr: Some(host),
+        footage: ctx.footage,
+        property_overrides: ctx.property_overrides,
+        media_overrides: ctx.media_overrides,
+    };
     let comp = ctx.comp_id.0;
     let path = layer.props.path_of(prop.uid).unwrap_or_else(|| format!("@{}", prop.uid));
     let resolver = Resolver { ctx, own: Own { comp, layer, prop, path: path.clone() } };
diff --git a/crates/expr/src/prelude.js b/crates/expr/src/prelude.js
index c2ca16736..8fe812590 100644
--- a/crates/expr/src/prelude.js
+++ b/crates/expr/src/prelude.js
@@ -207,6 +207,60 @@ function ease() { return __interp(__ease, arguments); }
 function easeIn() { return __interp(__easeIn, arguments); }
 function easeOut() { return __interp(__easeOut, arguments); }
 
+// Cubic-Bezier easing (the CSS cubic-bezier() shape): [x1, y1, x2, y2], with x1 / x2 in 0..1
+// and y1 / y2 free (overshoot included). Solves x(u) = x by Newton–Raphson, then by bisection
+// when Newton leaves 0..1 or the derivative vanishes, and returns y(u). A curve that is not four
+// finite numbers is linear, never an error.
+function __cubicBezier(curve) {
+  var x1, y1, x2, y2;
+  if (Array.isArray(curve) && curve.length === 4) {
+    x1 = curve[0]; y1 = curve[1]; x2 = curve[2]; y2 = curve[3];
+  }
+  if (typeof x1 !== 'number' || typeof y1 !== 'number' || typeof x2 !== 'number' || typeof y2 !== 'number' ||
+      !isFinite(x1) || !isFinite(y1) || !isFinite(x2) || !isFinite(y2)) {
+    return __lin;
+  }
+  x1 = Math.max(0, Math.min(1, x1));
+  x2 = Math.max(0, Math.min(1, x2));
+  function bx(u) { var v = 1 - u; return 3 * v * v * u * x1 + 3 * v * u * u * x2 + u * u * u; }
+  function dbx(u) { var v = 1 - u; return 3 * v * v * x1 + 6 * v * u * (x2 - x1) + 3 * u * u * (1 - x2); }
+  function by(u) { var v = 1 - u; return 3 * v * v * u * y1 + 3 * v * u * u * y2 + u * u * u; }
+  function dby(u) { var v = 1 - u; return 3 * v * v * y1 + 6 * v * u * (y2 - y1) + 3 * u * u * (1 - y2); }
+  return function (x) {
+    if (x <= 0) return 0;
+    if (x >= 1) return 1;
+    var u = x;
+    for (var i = 0; i < 8; i++) {
+      var f = bx(u) - x;
+      var d = dbx(u);
+      if (Math.abs(d) < 1e-12) break;
+      // Stop when the *value* is accurate: near the endpoints dy/dx is steep, so a residual in x
+      // alone can still mean a visible error in y (f * dy/dx estimates it).
+      if (Math.abs(f * dby(u) / d) < 1e-9) return by(u);
+      var n = u - f / d;
+      if (!(n >= 0 && n <= 1)) break;
+      u = n;
+    }
+    var lo = 0, hi = 1;
+    for (var j = 0; j < 60; j++) {
+      var mid = (lo + hi) / 2;
+      if (bx(mid) < x) lo = mid; else hi = mid;
+    }
+    return by((lo + hi) / 2);
+  };
+}
+
+// bezier(t, tMin, tMax, value1, value2, curve), or bezier(t, value1, value2, curve): the curve is
+// the sixth / fourth argument. Read it by position, not from the end: when it is missing or
+// unusable, the interpolation falls back to linear without consuming the last value.
+function bezier() {
+  var a = arguments, n = a.length;
+  if (n >= 6) return __interp(__cubicBezier(a[5]), [a[0], a[1], a[2], a[3], a[4]]);
+  if (n === 5) return __interp(__lin, [a[0], a[1], a[2], a[3], a[4]]);
+  if (n === 4) return __interp(__cubicBezier(a[3]), [a[0], a[1], a[2]]);
+  return __interp(__lin, [a[0], a[1], a[2]]);
+}
+
 // ---------------------------------------------------------------------------------------------
 // Random numbers and noise.
 
diff --git a/crates/expr/src/runtime.rs b/crates/expr/src/runtime.rs
index 29e5e4eda..84bfcdf3c 100644
--- a/crates/expr/src/runtime.rs
+++ b/crates/expr/src/runtime.rs
@@ -677,6 +677,7 @@ pub fn styled_doc(v: &serde_json::Value, own: &effectcraft_keyframe::TextDoc) ->
             let p0 = src.para(0);
             d.set_paras(vec![p0; d.para_count()]);
             d.stroke_over_fill = src.stroke_over_fill;
+            d.line_join = src.line_join;
         }
     }
     for op in v.get("ops").and_then(|o| o.as_array()).into_iter().flatten() {
diff --git a/crates/expr/src/tests.rs b/crates/expr/src/tests.rs
index cf13f02f8..55720a327 100644
--- a/crates/expr/src/tests.rs
+++ b/crates/expr/src/tests.rs
@@ -314,8 +314,78 @@ fn interpolation_with_arrays() {
     assert_eq!(f.pos("ease(time, 0, 1, [0, 0], [100, 50])", 1.0), [100.0, 50.0, 0.0]);
 }
 
-// ---- object model -----------------------------------------------------------------------------
+#[test]
+fn cubic_bezier_curves() {
+    let f = fx();
+    // ease(t, …) is cubic-bezier(1/3, 0, 2/3, 1): x(u) = u and y(u) = 3u² - 2u³.
+    assert_close!(f.num("bezier(0.25, 0, 1, 0, 100, [0.3333333333333333, 0, 0.6666666666666666, 1])", 0.0), f.num("ease(0.25, 0, 1, 0, 100)", 0.0));
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.3333333333333333, 0, 0.6666666666666666, 1])", 0.0), 50.0);
+    // Symmetric ease-in-out: slower at both ends, faster in the middle.
+    let early = f.num("bezier(0.25, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0);
+    let late = f.num("bezier(0.75, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0);
+    assert!(early < 25.0 && late > 75.0, "ease-in-out: {early}, {late}");
+    // Control points on the diagonal are linear.
+    assert_close!(f.num("bezier(0.3, 0, 1, 0, 100, [0, 0, 1, 1])", 0.0), 30.0);
+    // t is clamped to tMin..tMax; tMin == tMax behaves like the other helpers.
+    assert_close!(f.num("bezier(-1, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 0.0);
+    assert_close!(f.num("bezier(2, 0, 1, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 100.0);
+    assert_close!(f.num("bezier(5, 2, 2, 0, 100, [0.42, 0, 0.58, 1])", 0.0), 100.0);
+}
 
+#[test]
+fn cubic_bezier_short_form_arrays_and_fallbacks() {
+    let f = fx();
+    // Short form: no tMin / tMax.
+    assert_close!(f.num("bezier(0.25, 10, 20, [0, 0, 1, 1])", 0.0), 12.5);
+    assert_eq!(f.pos("bezier(time, 0, 1, [0, 0], [100, 50], [0.42, 0, 0.58, 1])", 1.0), [100.0, 50.0, 0.0]);
+    // y outside 0..1 overshoots, as CSS allows.
+    let over = f.num("bezier(0.5, 0, 1, 0, 100, [0.5, 2, 0.5, 2])", 0.0);
+    assert!(over > 100.0, "overshoot: {over}");
+    // A curve that is not four finite numbers falls back to linear instead of throwing.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [1, 0])", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, 'ease')", 0.0), 50.0);
+    // A missing or unusable curve must not consume the last value: read the curve by position.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100)", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 100)", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 100, [1, 0])", 0.0), 50.0);
+    let v = f.ev(f.shape, "contents/#1/contents/fill/color", "bezier(0.5, 0, 1, [0, 0, 0, 1], [1, 1, 1, 1])", 0.0).unwrap();
+    assert_eq!(v, Value::Color([0.5, 0.5, 0.5, 1.0]));
+    // Exactly four values are a curve; extra ones mean the curve is malformed, so linear.
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.42, 0, 0.58, 1, 0])", 0.0), 50.0);
+    assert_close!(f.num("bezier(0.5, 0, 1, 0, 100, [0.42, 0, 0.58, 1, 2, 3])", 0.0), 50.0);
+    // x control points outside 0..1 are clamped, as CSS requires.
+    let v = f.num("bezier(0.5, 0, 1, 0, 100, [-1, 0, 2, 1])", 0.0);
+    assert!(v.is_finite(), "clamped curve: {v}");
+}
+
+#[test]
+fn cubic_bezier_is_accurate_near_the_endpoints() {
+    /// The value the curve reaches at `x`, by bisection on its monotone x(u).
+    fn reference(x1: f64, y1: f64, x2: f64, y2: f64, x: f64) -> f64 {
+        let bx = |u: f64| 3.0 * (1.0 - u) * (1.0 - u) * u * x1 + 3.0 * (1.0 - u) * u * u * x2 + u * u * u;
+        let by = |u: f64| 3.0 * (1.0 - u) * (1.0 - u) * u * y1 + 3.0 * (1.0 - u) * u * u * y2 + u * u * u;
+        let (mut lo, mut hi) = (0.0f64, 1.0f64);
+        for _ in 0..100 {
+            let mid = 0.5 * (lo + hi);
+            if bx(mid) < x {
+                lo = mid;
+            } else {
+                hi = mid;
+            }
+        }
+        by(0.5 * (lo + hi))
+    }
+    // Steep curves: a residual in x is not a residual in y near the endpoints (dy/dx is in the
+    // thousands), so the solver stops on the estimated y error instead.
+    let f = fx();
+    for (c, x) in [([0.0, 1000.0, 1.0, 1.0], 1e-6), ([0.0, 100.0, 1.0, 0.0], 1e-9), ([0.8, -500.0, 1.0, 1.0], 0.999999)] {
+        let got = f.num(&format!("bezier({x}, 0, 1, [{}, {}, {}, {}])", c[0], c[1], c[2], c[3]), 0.0);
+        let want = reference(c[0], c[1], c[2], c[3], x);
+        assert!((got - want).abs() < 1e-6, "curve {c:?} at {x}: {got} vs {want}");
+    }
+}
+
+// ---- object model -----------------------------------------------------------------------------
 #[test]
 fn comp_attributes() {
     let f = fx();
@@ -908,6 +978,49 @@ fn source_rect_at_time() {
     assert!((s[0] + 31.0).abs() < 2.0 && (s[1] + 16.0).abs() < 2.0 && (s[2] - 62.0).abs() < 3.0, "{s:?}");
 }
 
+#[test]
+fn source_dimensions_follow_media_replacement() {
+    let mut p = Project::default();
+    let comp = Comp::new(200, 100, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let cid = p.add_item("Main", Label::Sandstone, None, ItemKind::Comp(comp.clone().into()));
+    let footage = |p: &mut Project, name: &str, width, height| {
+        p.add_item(
+            name,
+            Label::SeaFoam,
+            None,
+            ItemKind::Footage(effectcraft_project::Footage {
+                path: name.into(),
+                kind: effectcraft_project::FootageKind::Still,
+                width,
+                height,
+                has_video: true,
+                ..Default::default()
+            }),
+        )
+    };
+    let original = footage(&mut p, "original.png", 100, 80);
+    let replacement = footage(&mut p, "replacement.png", 30, 40);
+    let mut l = build::layer(&mut p, &comp, "Clip", LayerSource::Footage { item: original }, (100, 80), None);
+    l.props.prop_mut(ROT).unwrap().expr =
+        Some(Expression { text: "thisLayer.width + thisLayer.height + thisLayer.source.width + sourceRectAtTime().width".into(), enabled: true });
+    let lid = l.id;
+    p.comp_mut(cid).unwrap().layers.push(l);
+    let c = p.comp(cid).unwrap();
+    let l = c.layer(lid).unwrap();
+    let media = effectcraft_render::MediaOverride::new(lid, replacement);
+    let ctx = EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: c,
+        time: Tick::ZERO,
+        expr: Some(&Expressions),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[media],
+    };
+    assert_eq!(ctx.value(l, l.props.prop(ROT).unwrap()), Value::Scalar(130.0));
+}
+
 // ---- colour -----------------------------------------------------------------------------------
 
 #[test]
@@ -1115,7 +1228,16 @@ fn text_expression_selector_values() {
     let sel_of = |p: &Project| {
         let c = p.comp(cid).unwrap();
         let l = c.layer(lid).unwrap();
-        let ctx = EvalCtx { project: p, comp_id: cid, comp: c, time: Tick::ZERO, expr: Some(&Expressions), footage: None };
+        let ctx = EvalCtx {
+            project: p,
+            comp_id: cid,
+            comp: c,
+            time: Tick::ZERO,
+            expr: Some(&Expressions),
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         let doc = effectcraft_render::text::source_text(&ctx, l).unwrap();
         let lay = effectcraft_text::layout_doc(&doc);
         let anim = l.props.group("text/animators/#1").unwrap();
diff --git a/crates/expr/src/tests/fuzz.rs b/crates/expr/src/tests/fuzz.rs
index 1bfaf8c16..37b28c415 100644
--- a/crates/expr/src/tests/fuzz.rs
+++ b/crates/expr/src/tests/fuzz.rs
@@ -93,6 +93,8 @@ const SEEDS: &[&str] = &[
     "linear(time, 0, 1, 0, 100)",
     "ease(time, 0, 2, [0, 0], [100, 50])",
     "easeIn(time, 0, 1, 0, 360) + easeOut(time, 1, 2, 0, 10)",
+    "bezier(time, 0, 1, 0, 100, [0.42, 0, 0.58, 1])",
+    "bezier(time, [0, 0], [100, 50], [0.25, 0.1, 0.25, 1])",
     "clamp(value * 2, 0, 100)",
     "length([0, 0], [3, 4]) + dot([1, 0], [0, 1]) + cross([1, 0, 0], [0, 1, 0])[2]",
     "normalize([3, 4])[0] * degreesToRadians(180)",
diff --git a/crates/gpu/src/bokeh.rs b/crates/gpu/src/bokeh.rs
index 39dc0bdea..a3f05bf12 100644
--- a/crates/gpu/src/bokeh.rs
+++ b/crates/gpu/src/bokeh.rs
@@ -10,8 +10,9 @@ use crate::context::{Enc, GpuImage, Params};
 
 /// Blur `src` (an unpadded plane buffer) as `d` says. Returns the padded, blurred image.
 pub(crate) fn apply(e: &mut Enc, src: &GpuImage, d: &PlaneDof) -> Option<GpuImage> {
-    let (w, h) = (src.width + 2 * d.pad, src.height + 2 * d.pad);
-    if !e.g.fits(w + 1, h) || d.radius.len() != w as usize * h as usize || d.levels.is_empty() {
+    // Saturating, so an oversized padding is refused by `fits` below instead of wrapping around.
+    let (w, h) = (src.width.saturating_add(d.pad.saturating_mul(2)), src.height.saturating_add(d.pad.saturating_mul(2)));
+    if !e.g.fits(w.saturating_add(1), h) || d.radius.len() != w as usize * h as usize || d.levels.is_empty() {
         return None;
     }
     let padded = e.image(w, h);
diff --git a/crates/gpu/src/effects.rs b/crates/gpu/src/effects.rs
index 1e97b7eab..645f1cc39 100644
--- a/crates/gpu/src/effects.rs
+++ b/crates/gpu/src/effects.rs
@@ -46,6 +46,7 @@ impl GBuf {
 
     /// Buf::pad: grow by `pad` transparent pixels on every side.
     pub fn pad(&mut self, e: &mut Enc, pad: u32) -> Option<()> {
+        let pad = effectcraft_effects::pad_within_budget(self.img.width, self.img.height, pad);
         if pad == 0 {
             return Some(());
         }
diff --git a/crates/gpu/src/tests/adv3d.rs b/crates/gpu/src/tests/adv3d.rs
index 21422aa6b..f09798119 100644
--- a/crates/gpu/src/tests/adv3d.rs
+++ b/crates/gpu/src/tests/adv3d.rs
@@ -96,7 +96,16 @@ pub(crate) fn scene_project() -> (Project, ItemId) {
 
 pub(crate) fn scene(p: &Project, cid: ItemId) -> Scene {
     let r = Renderer::new(p, &NoFootage, RenderOpts::default());
-    let ctx = EvalCtx { project: p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx {
+        project: p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let run: Vec<&effectcraft_project::Layer> = ctx.comp.layers.iter().rev().filter(|l| l.is_3d() && l.has_video()).collect();
     adv::scene_of(&r, &ctx, &run, (ctx.comp.width, ctx.comp.height))
 }
@@ -277,7 +286,16 @@ pub(crate) fn off_share(a: &[[f32; 4]], b: &[[f32; 4]]) -> (f64, f32) {
 }
 
 pub(crate) fn run_of(p: &Project, cid: ItemId) -> (EvalCtx<'_>, Vec<&effectcraft_project::Layer>) {
-    let ctx = EvalCtx { project: p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = EvalCtx {
+        project: p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let run: Vec<&effectcraft_project::Layer> = ctx.comp.layers.iter().rev().filter(|l| l.is_3d() && l.has_video()).collect();
     (ctx, run)
 }
diff --git a/crates/gpu/src/walk.rs b/crates/gpu/src/walk.rs
index 78a6857fb..d4d7a62a1 100644
--- a/crates/gpu/src/walk.rs
+++ b/crates/gpu/src/walk.rs
@@ -89,7 +89,7 @@ fn draw_comp<'a>(e: &mut Enc, r: &Renderer<'a>, ctx: &EvalCtx<'a>, canvas: &mut
             i = j;
         } else {
             match r.collapsed(ctx, visible[i]) {
-                Some(item) => draw_collapsed(e, r, ctx, visible[i], item, canvas)?,
+                Some(collapsed) => draw_collapsed(e, r, ctx, visible[i], &collapsed, canvas)?,
                 None => draw_layer(e, r, ctx, visible[i], canvas)?,
             }
             i += 1;
@@ -187,19 +187,26 @@ fn draw_split(e: &mut Enc, r: &Renderer, ctx: &EvalCtx, split: &effectcraft_rend
     Some(cv)
 }
 
-fn draw_collapsed<'a>(e: &mut Enc, r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut GpuImage) -> Option<()> {
+fn draw_collapsed<'a>(
+    e: &mut Enc,
+    r: &Renderer<'a>,
+    ctx: &EvalCtx<'a>,
+    layer: &'a Layer,
+    collapsed: &effectcraft_render::Collapsed,
+    canvas: &mut GpuImage,
+) -> Option<()> {
     let opacity = r.layer_opacity(ctx, layer);
     if opacity <= 0.0 {
         return Some(());
     }
     let matte = r.track_matte(ctx, layer).is_some();
     if layer.blend_mode == BlendMode::Normal && !matte && !layer.preserve_transparency {
-        if let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, opacity) {
+        if let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, opacity) {
             draw_comp(e, &sub, &nctx, canvas)?;
         }
         return Some(());
     }
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, 1.0) else { return Some(()) };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, 1.0) else { return Some(()) };
     let mut iso = e.zeros(canvas.width, canvas.height);
     draw_comp(e, &sub, &nctx, &mut iso)?;
     composite_iso(e, r, ctx, layer, iso, canvas, opacity)
diff --git a/crates/host/src/tests.rs b/crates/host/src/tests.rs
index a73f15937..3114c2ddb 100644
--- a/crates/host/src/tests.rs
+++ b/crates/host/src/tests.rs
@@ -269,7 +269,16 @@ fn value(s: &effectcraft_engine::Session, l: u64, path: &str) -> effectcraft_eng
     let cid = s.active_comp_id().unwrap();
     let comp = s.project.comp(cid).unwrap();
     let layer = comp.layer(effectcraft_engine::project::LayerId(l)).unwrap();
-    let ctx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: Default::default(), expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: Default::default(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     ctx.value(layer, layer.props.prop(path).unwrap())
 }
 
@@ -523,8 +532,16 @@ fn stereo_rig_expressions_follow_the_master_camera() {
     let v3 = |s: &effectcraft_engine::Session, path: &str| {
         let comp = s.project.comp(left).unwrap();
         let layer = &comp.layers[0];
-        let ctx =
-            effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: left, comp, time: Default::default(), expr: s.expr.as_deref(), footage: None };
+        let ctx = effectcraft_engine::render::EvalCtx {
+            project: &s.project,
+            comp_id: left,
+            comp,
+            time: Default::default(),
+            expr: s.expr.as_deref(),
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         ctx.value(layer, layer.props.prop(path).unwrap()).as_vec3()
     };
     let close = |a: [f64; 3], b: [f64; 3]| (0..3).all(|i| (a[i] - b[i]).abs() < 1e-6);
diff --git a/crates/host/tests/it/main.rs b/crates/host/tests/it/main.rs
index 1e60e5ab7..826363edb 100644
--- a/crates/host/tests/it/main.rs
+++ b/crates/host/tests/it/main.rs
@@ -12,4 +12,5 @@ mod relink;
 mod tga_import;
 mod timeline_interop;
 mod vector_import;
+mod wav_markers;
 mod webm_metadata;
diff --git a/crates/host/tests/it/wav_markers.rs b/crates/host/tests/it/wav_markers.rs
new file mode 100644
index 000000000..98d2685dc
--- /dev/null
+++ b/crates/host/tests/it/wav_markers.rs
@@ -0,0 +1,126 @@
+//! Markers a WAV file carries, through the fully wired session (media import included): the
+//! layer made from the file starts with them, and Update Markers From Source copies them again,
+//! through its bound `layers` parameter as well as the selection, as one undo step.
+
+use effectcraft_engine::Session;
+use effectcraft_project::LayerSource;
+use serde_json::json;
+
+/// The comments of a layer's markers, in time order.
+fn names(s: &mut Session, layer: u64) -> Vec<String> {
+    let list = s.execute_checked("markers.list", json!({"layer": layer})).unwrap();
+    list.as_array().unwrap().iter().map(|m| m["comment"].as_str().unwrap().to_string()).collect()
+}
+
+/// A one-second mono 8 kHz WAV with the named cue points `(id, sample, name)` (a `cue ` chunk and a
+/// `LIST` `adtl`).
+fn marker_wav(points: &[(u32, u32, &str)]) -> Vec<u8> {
+    fn chunk(id: &[u8; 4], body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend((body.len() as u32).to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+    let mut fmt = Vec::new();
+    fmt.extend(1u16.to_le_bytes());
+    fmt.extend(1u16.to_le_bytes());
+    fmt.extend(8000u32.to_le_bytes());
+    fmt.extend(16000u32.to_le_bytes());
+    fmt.extend(2u16.to_le_bytes());
+    fmt.extend(16u16.to_le_bytes());
+    let mut cue = (points.len() as u32).to_le_bytes().to_vec();
+    let mut adtl = b"adtl".to_vec();
+    for &(id, at, name) in points {
+        for v in [id, 0] {
+            cue.extend(v.to_le_bytes());
+        }
+        cue.extend(b"data");
+        for v in [0, 0, at] {
+            cue.extend(u32::to_le_bytes(v));
+        }
+        let mut labl = id.to_le_bytes().to_vec();
+        labl.extend(name.as_bytes());
+        labl.push(0);
+        adtl.extend(chunk(b"labl", &labl));
+    }
+    let mut body = b"WAVE".to_vec();
+    for c in [chunk(b"fmt ", &fmt), chunk(b"data", &[0; 16000]), chunk(b"cue ", &cue), chunk(b"LIST", &adtl)] {
+        body.extend(c);
+    }
+    let mut file = b"RIFF".to_vec();
+    file.extend((body.len() as u32).to_le_bytes());
+    file.extend(body);
+    file
+}
+
+/// A WAV's cue points become markers on the layer made from it, named as in the file, and
+/// Update Markers From Source brings back one that was deleted (through the fully wired session,
+/// media import included).
+#[test]
+fn a_wav_layer_starts_with_the_markers_in_its_file() {
+    let mut s = effectcraft_host::session();
+    s.execute_checked("comp.new", json!({"name": "C", "width": 64, "height": 48, "frameRate": 30, "duration": 2})).unwrap();
+    let dir = std::env::temp_dir().join(format!("effectcraft-host-wav-markers-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("cues.wav");
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro"), (2, 4000, "Middle")])).unwrap();
+    let r = s.execute_checked("file.import", json!({"paths": [path.to_string_lossy()], "addToComp": true})).unwrap();
+    assert_eq!(r["errors"], json!([]), "{r}");
+    let layer = s.active_comp().unwrap().layers.iter().find(|l| matches!(l.source, LayerSource::Footage { .. })).unwrap().id.0;
+    let list = s.execute_checked("markers.list", json!({"layer": layer})).unwrap();
+    let marks: Vec<(String, f64)> =
+        list.as_array().unwrap().iter().map(|m| (m["comment"].as_str().unwrap().to_string(), m["time"].as_f64().unwrap())).collect();
+    assert_eq!(marks, [("Intro".to_string(), 0.0), ("Middle".to_string(), 0.5)]);
+    s.execute_checked("markers.delete", json!({"layer": layer, "index": 0})).unwrap();
+    assert_eq!(names(&mut s, layer), ["Middle"]);
+    s.execute_checked("layer.select", json!({"layers": [layer]})).unwrap();
+    // The bound `layers` parameter (what a script or the menu's own binding passes) brings the marker back...
+    let r = s.execute_checked("layer.updateMarkersFromSource", json!({"layers": [layer]})).unwrap();
+    assert_eq!(r["added"], 1);
+    assert_eq!(names(&mut s, layer), ["Intro", "Middle"]);
+    // ...as one undo step: undo removes it again, redo restores it.
+    assert!(s.undo());
+    assert_eq!(names(&mut s, layer), ["Middle"]);
+    assert!(s.redo());
+    assert_eq!(names(&mut s, layer), ["Intro", "Middle"]);
+    // The selection route (no parameter) finds nothing more to add.
+    assert_eq!(s.execute_checked("layer.updateMarkersFromSource", json!({})).unwrap()["added"], 0);
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+/// Reload Footage re-reads the markers the file carries: a cue point added to the file after the
+/// import is available to Update Markers From Source (and a layer already made keeps its own).
+#[test]
+fn reloading_a_wav_picks_up_cue_points_added_to_the_file() {
+    let mut s = effectcraft_host::session();
+    s.execute_checked("comp.new", json!({"name": "C", "width": 64, "height": 48, "frameRate": 30, "duration": 2})).unwrap();
+    let dir = std::env::temp_dir().join(format!("effectcraft-host-wav-reload-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("cues.wav");
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro")])).unwrap();
+    let r = s.execute_checked("file.import", json!({"paths": [path.to_string_lossy()], "addToComp": true})).unwrap();
+    assert_eq!(r["errors"], json!([]), "{r}");
+    let (layer, item) = s
+        .active_comp()
+        .unwrap()
+        .layers
+        .iter()
+        .find_map(|l| match l.source {
+            LayerSource::Footage { item } => Some((l.id.0, item.0)),
+            _ => None,
+        })
+        .unwrap();
+    assert_eq!(names(&mut s, layer), ["Intro"]);
+    // The file gains a cue point; the layer does not change until asked.
+    std::fs::write(&path, marker_wav(&[(1, 0, "Intro"), (2, 4000, "Added later")])).unwrap();
+    let r = s.execute_checked("file.reloadFootage", json!({"items": [item]})).unwrap();
+    assert_eq!(r["reloaded"], 1, "{r}");
+    assert_eq!(names(&mut s, layer), ["Intro"]);
+    let r = s.execute_checked("layer.updateMarkersFromSource", json!({"layers": [layer]})).unwrap();
+    assert_eq!(r["added"], 1);
+    assert_eq!(names(&mut s, layer), ["Intro", "Added later"]);
+    let _ = std::fs::remove_dir_all(&dir);
+}
diff --git a/crates/keyframe/src/lib.rs b/crates/keyframe/src/lib.rs
index f2d94f177..f0dd4849c 100644
--- a/crates/keyframe/src/lib.rs
+++ b/crates/keyframe/src/lib.rs
@@ -15,7 +15,7 @@ pub mod value;
 
 use effectcraft_time::{TICKS_PER_SECOND, Tick};
 use serde::{Deserialize, Serialize};
-pub use text_doc::{BaselineOption, CharStyle, Composer, Direction, FigureStyle, FigureWidth, Kerning, OpenType, ParaStyle, StyleRun};
+pub use text_doc::{BaselineOption, CharStyle, Composer, Direction, FigureStyle, FigureWidth, Kerning, LineJoin, OpenType, ParaStyle, StyleRun};
 pub use value::{FeatherPoint, Gradient, Justify, ShapePath, TextDoc, Value};
 
 /// Temporal interpolation on one side of a keyframe.
diff --git a/crates/keyframe/src/text_doc.rs b/crates/keyframe/src/text_doc.rs
index 6c1e5b843..96a8b6be3 100644
--- a/crates/keyframe/src/text_doc.rs
+++ b/crates/keyframe/src/text_doc.rs
@@ -179,6 +179,31 @@ pub enum Composer {
 fn single_line() -> Composer {
     Composer::SingleLine
 }
+
+/// How the corners of a text stroke are drawn (Character panel Line Join).
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum LineJoin {
+    /// Sharp corners (AE's default for new text).
+    #[default]
+    Miter,
+    Round,
+    Bevel,
+}
+
+impl LineJoin {
+    pub fn parse(s: &str) -> Option<LineJoin> {
+        Some(match s.to_ascii_lowercase().as_str() {
+            "miter" => LineJoin::Miter,
+            "round" => LineJoin::Round,
+            "bevel" => LineJoin::Bevel,
+            _ => return None,
+        })
+    }
+}
+
+fn round_join() -> LineJoin {
+    LineJoin::Round
+}
 fn yes() -> bool {
     true
 }
@@ -402,6 +427,9 @@ pub struct TextDoc {
     pub apply_fill: bool,
     pub apply_stroke: bool,
     pub stroke_over_fill: bool,
+    /// Documents saved before line joins existed drew round joins.
+    #[serde(default = "round_join")]
+    pub line_join: LineJoin,
     pub tracking: f64,
     /// None = auto (120% of size).
     pub leading: Option<f64>,
@@ -463,6 +491,7 @@ impl Default for TextDoc {
             apply_fill: true,
             apply_stroke: false,
             stroke_over_fill: true,
+            line_join: LineJoin::Miter,
             tracking: 0.0,
             leading: None,
             justify: Justify::Left,
@@ -909,6 +938,10 @@ impl TextDoc {
                 self.stroke_over_fill = v.as_bool().ok_or("strokeOverFill: expected a boolean")?;
                 return Ok(true);
             }
+            "lineJoin" => {
+                self.line_join = v.as_str().and_then(LineJoin::parse).ok_or("lineJoin: expected miter|round|bevel")?;
+                return Ok(true);
+            }
             "vertical" => {
                 self.vertical = v.as_bool().ok_or("vertical: expected a boolean")?;
                 return Ok(true);
@@ -1423,6 +1456,8 @@ mod tests {
         assert!(d.is_uniform());
         assert_eq!(d.style_at(2).size, 50.0);
         assert_eq!(d.composer, Composer::SingleLine, "old box text keeps greedy breaking");
+        assert_eq!(d.line_join, LineJoin::Round, "old strokes keep their round corners");
+        assert_eq!(TextDoc::default().line_join, LineJoin::Miter);
         assert!(d.ligatures);
         assert_eq!(d.kerning, Kerning::Metrics);
         // Round trip with runs.
diff --git a/crates/media/Cargo.toml b/crates/media/Cargo.toml
index 0ef01d831..52a375fef 100644
--- a/crates/media/Cargo.toml
+++ b/crates/media/Cargo.toml
@@ -12,6 +12,7 @@ workspace = true
 [dependencies]
 craft-docpath = { workspace = true }
 effectcraft-time = { workspace = true }
+effectcraft-color = { workspace = true }
 effectcraft-project = { workspace = true }
 effectcraft-raster = { workspace = true }
 effectcraft-render = { workspace = true }
diff --git a/crates/media/src/lib.rs b/crates/media/src/lib.rs
index 306f8d860..946e0d12a 100644
--- a/crates/media/src/lib.rs
+++ b/crates/media/src/lib.rs
@@ -25,6 +25,7 @@ pub use layered::vector_doc;
 mod pool;
 mod probe;
 mod stream;
+mod wav_markers;
 mod webp_anim;
 
 pub use pool::{DEFAULT_BUDGET, MediaPool, PoolStats};
diff --git a/crates/media/src/probe.rs b/crates/media/src/probe.rs
index 8197cd61f..41b50b0f4 100644
--- a/crates/media/src/probe.rs
+++ b/crates/media/src/probe.rs
@@ -23,6 +23,7 @@ pub fn probe(path: impl AsRef<Path>) -> Result<Footage> {
         let turn = header.as_deref().map_or(Orientation::NoTransforms, video_turn);
         turn_footage(&mut f, turn);
         correct_rate(&mut f, header.as_deref().and_then(video_rate));
+        trim_to_edits(&mut f, header.as_deref().and_then(video_shown));
         return Ok(f);
     }
     let bytes = crate::read_regular_file(path).map_err(|e| MediaError::Io(format!("{}: {e}", path.display())))?;
@@ -107,13 +108,45 @@ pub fn probe_bytes(path: &str, bytes: Arc<[u8]>) -> Result<Footage> {
     let name = Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_else(|| path.to_string());
     let turn = video_turn(&bytes);
     let rate = video_rate(&bytes);
+    let shown = video_shown(&bytes);
+    // A WAV's cue points and XMP markers become the footage's markers.
+    let markers = crate::wav_markers::read(&bytes);
     let src = filmcraft_codecs::open_bytes(&name, bytes)?;
     let mut f = footage_from_info(path, src.info());
+    f.markers = markers;
     turn_footage(&mut f, turn);
     correct_rate(&mut f, rate);
+    trim_to_edits(&mut f, shown);
     Ok(f)
 }
 
+/// A movie lasts as long as its video edit list shows (#2592): the reader reports the media
+/// duration (`mdhd`), which for H.264 with B-frames runs past the last shown frame by the
+/// encoder delay the edit list trims (75 frames at 25 fps read as 3.04 s). Never lengthens.
+fn trim_to_edits(f: &mut Footage, shown: Option<Tick>) {
+    if f.kind == FootageKind::Video
+        && let Some(shown) = shown.filter(|s| *s > Tick::ZERO && *s < f.duration)
+    {
+        f.duration = shown;
+    }
+}
+
+/// How long the video track's edit list shows its media (`elst` segments, movie timescale):
+/// `None` without edits, or with an empty edit (a delayed start keeps the reader's duration).
+fn video_shown(bytes: &[u8]) -> Option<Tick> {
+    let file = filmcraft_isobmff::open(bytes).ok()?;
+    let t = file.tracks.iter().find(|t| t.kind == filmcraft_isobmff::TrackKind::Video && !t.samples.is_empty())?;
+    edits_shown(&t.edits, file.timescale)
+}
+
+fn edits_shown(edits: &[filmcraft_isobmff::Edit], timescale: u32) -> Option<Tick> {
+    if edits.is_empty() || timescale == 0 || edits.iter().any(|e| e.media_time < 0) {
+        return None;
+    }
+    let units = edits.iter().try_fold(0u64, |acc, e| acc.checked_add(e.segment_duration))?;
+    Some(Tick::from_units(i64::try_from(units).ok()?, i64::from(timescale)))
+}
+
 /// A movie's frame rate as its frame durations average to ([`video_rate`]), where the reader's
 /// own estimate misreads it.
 fn correct_rate(f: &mut Footage, rate: Option<FrameRate>) {
@@ -319,6 +352,24 @@ fn averaged_rate(timescale: u32, durations: impl Iterator<Item = u32>) -> Option
 mod tests {
     use super::*;
 
+    /// #2592: an encoder-delayed H.264 track's edit list shows 75 frames at 25 fps (3 s at a
+    /// 1000 timescale), though its media runs a frame longer; empty edits and no edits leave it.
+    #[test]
+    fn the_edit_list_trims_a_movie_to_the_frames_it_shows() {
+        let edit = |segment_duration, media_time| filmcraft_isobmff::Edit { segment_duration, media_time, media_rate: 0x0001_0000 };
+        let shown = edits_shown(&[edit(3000, 1024)], 1000);
+        assert_eq!(shown, Some(Tick::from_units(3, 1)));
+        let mut f = Footage { kind: FootageKind::Video, duration: Tick::from_units(76, 25), ..Footage::default() };
+        trim_to_edits(&mut f, shown);
+        assert_eq!(f.duration, Tick::from_units(75, 25));
+        // Never longer than the reader's duration, and only for video.
+        trim_to_edits(&mut f, Some(Tick::from_units(4, 1)));
+        assert_eq!(f.duration, Tick::from_units(75, 25));
+        assert_eq!(edits_shown(&[edit(1000, -1), edit(3000, 0)], 1000), None);
+        assert_eq!(edits_shown(&[], 1000), None);
+        assert_eq!(edits_shown(&[edit(3000, 0)], 0), None);
+    }
+
     /// Durations (in 1/`timescale` s) of `n` frames at `rate` whose times are rounded to the timescale.
     fn rounded(rate: FrameRate, timescale: i64, n: i64) -> Vec<u32> {
         let at = |k: i64| (2 * k * timescale * rate.den + rate.num) / (2 * rate.num);
diff --git a/crates/media/src/wav_markers.rs b/crates/media/src/wav_markers.rs
new file mode 100644
index 000000000..ca40824b6
--- /dev/null
+++ b/crates/media/src/wav_markers.rs
@@ -0,0 +1,517 @@
+//! Markers a WAV file carries, read from its RIFF chunks.
+//!
+//! Two encodings are read and merged:
+//! - **Cue points** (the standard): a `cue ` chunk with one point per marker, named by `labl` (or
+//!   `note`) sub-chunks of a `LIST` `adtl` chunk, and given a length by `ltxt`.
+//! - **XMP** (Adobe's tools): an `_PMX` chunk holding an XMP packet whose `xmpDM:markers` list has
+//!   one entry per marker (`xmpDM:startTime`, `xmpDM:duration`, `xmpDM:name`), counted in frames
+//!   of `xmpDM:frameRate` (`f44100` for samples at 44.1 kHz).
+//!
+//! RF64 files (WAVs over 4 GB) carry a `0xFFFFFFFF` size for a chunk too big for 32 bits and give its real size in a
+//! `ds64` chunk; those sizes are resolved so the chunks after the audio are still found.
+//!
+//! The file is untrusted input: every read is bounds-checked, sizes use checked arithmetic, and
+//! the number of markers, of `adtl` sub-chunks looked at and the size of the XMP packet are capped.
+
+use std::collections::{HashMap, HashSet};
+
+use effectcraft_color::Label;
+use effectcraft_project::Marker;
+use effectcraft_time::Tick;
+
+/// Most markers read from one file.
+pub const MAX_MARKERS: usize = 10_000;
+/// Largest XMP packet read (bytes).
+const MAX_XMP: usize = 4 << 20;
+/// Most `adtl` sub-chunks (`labl`, `note`, `ltxt`) looked at in one file: a few per cue point is plenty.
+const MAX_ADTL_RECORDS: usize = 4 * MAX_MARKERS;
+/// Most entries read from an RF64 file's `ds64` size table.
+const MAX_DS64_TABLE: usize = 1_024;
+
+fn u32_at(b: &[u8], at: usize) -> Option<u32> {
+    let s = b.get(at..at.checked_add(4)?)?;
+    Some(u32::from_le_bytes(s.try_into().ok()?))
+}
+
+fn u64_at(b: &[u8], at: usize) -> Option<u64> {
+    let s = b.get(at..at.checked_add(8)?)?;
+    Some(u64::from_le_bytes(s.try_into().ok()?))
+}
+
+/// The text of a NUL-terminated label (the rest of the chunk), lossily decoded.
+fn label(b: &[u8]) -> String {
+    let end = b.iter().position(|&c| c == 0).unwrap_or(b.len());
+    String::from_utf8_lossy(b.get(..end).unwrap_or_default()).trim().to_string()
+}
+
+fn secs(frames: f64, rate: f64) -> Tick {
+    if rate > 0.0 && frames.is_finite() { Tick::from_seconds_f64((frames / rate).max(0.0)) } else { Tick::ZERO }
+}
+
+/// Whether `bytes` start a RIFF/WAVE file.
+pub fn is_wav(bytes: &[u8]) -> bool {
+    matches!(bytes.get(0..4), Some(b"RIFF" | b"RF64")) && bytes.get(8..12) == Some(b"WAVE")
+}
+
+/// The sizes an RF64 file's `ds64` chunk gives for chunks too big for the 32-bit size field.
+struct Ds64 {
+    /// The `data` chunk's size.
+    data: u64,
+    /// Other chunks: `(id, size)`.
+    table: Vec<([u8; 4], u64)>,
+}
+
+impl Ds64 {
+    /// The real size of chunk `id`, when the file says.
+    fn size_of(&self, id: &[u8; 4]) -> Option<u64> {
+        if id == b"data" { Some(self.data) } else { self.table.iter().find(|(t, _)| t == id).map(|(_, size)| *size) }
+    }
+}
+
+/// The `ds64` chunk of an RF64 file (`RF64`, size, `WAVE`, then `ds64`); `None` for any other file or one whose
+/// `ds64` doesn't fit.
+fn ds64(bytes: &[u8]) -> Option<Ds64> {
+    if bytes.get(0..4) != Some(b"RF64") || bytes.get(12..16) != Some(b"ds64") {
+        return None;
+    }
+    let size = usize::try_from(u32_at(bytes, 16)?).ok()?;
+    let body = bytes.get(20..20usize.checked_add(size)?)?;
+    // riff size (8), data size (8), sample count (8), table length (4), then `(id, size)` entries of 12 bytes
+    let data = u64_at(body, 8)?;
+    let entries = usize::try_from(u32_at(body, 24)?).ok()?;
+    let mut table = Vec::new();
+    for i in 0..entries.min(MAX_DS64_TABLE) {
+        let at = 28usize.checked_add(i.checked_mul(12)?)?;
+        let id = <[u8; 4]>::try_from(body.get(at..at.checked_add(4)?)?).ok()?;
+        table.push((id, u64_at(body, at + 4)?));
+    }
+    Some(Ds64 { data, table })
+}
+
+/// The chunks of a WAVE file as `(id, body)`, stopping at the first one that doesn't fit.
+fn chunks(bytes: &[u8]) -> Vec<([u8; 4], &[u8])> {
+    let big = ds64(bytes);
+    let mut out = Vec::new();
+    let mut at = 12usize;
+    while let Some(head) = bytes.get(at..at.saturating_add(8)) {
+        let (Ok(id), Some(field)) = (<[u8; 4]>::try_from(&head[..4]), u32_at(head, 4)) else { break };
+        // In an RF64 file a size field of 0xFFFFFFFF stands for the size `ds64` gives.
+        let size = match &big {
+            Some(d) if field == u32::MAX => d.size_of(&id).unwrap_or(u64::from(field)),
+            _ => u64::from(field),
+        };
+        let start = at.saturating_add(8);
+        let Some(end) = usize::try_from(size).ok().and_then(|n| start.checked_add(n)) else { break };
+        let Some(body) = bytes.get(start..end) else { break };
+        out.push((id, body));
+        // Chunks are padded to an even size.
+        at = end.saturating_add(end & 1);
+    }
+    out
+}
+
+/// The markers `bytes` carry, in time order (empty for anything that isn't a WAV with markers).
+pub fn read(bytes: &[u8]) -> Vec<Marker> {
+    if !is_wav(bytes) {
+        return Vec::new();
+    }
+    let chunks = chunks(bytes);
+    let rate = chunks.iter().find(|(id, _)| id == b"fmt ").and_then(|(_, b)| u32_at(b, 4)).map_or(0.0, f64::from);
+    let mut out = cue_markers(&chunks, rate);
+    if let Some((_, xmp)) = chunks.iter().find(|(id, _)| id == b"_PMX") {
+        // Tools that write both encodings repeat each marker.
+        let mut seen: HashSet<(String, Tick)> = out.iter().map(|o| (o.comment.clone(), o.time)).collect();
+        for m in xmp_markers(xmp, rate) {
+            if seen.insert((m.comment.clone(), m.time)) {
+                out.push(m);
+            }
+        }
+    }
+    out.truncate(MAX_MARKERS);
+    out.sort_by_key(|m| m.time);
+    out
+}
+
+/// Cue points named and sized by the `adtl` list.
+fn cue_markers(chunks: &[([u8; 4], &[u8])], rate: f64) -> Vec<Marker> {
+    let Some((_, cue)) = chunks.iter().find(|(id, _)| id == b"cue ") else { return Vec::new() };
+    let count = (u32_at(cue, 0).unwrap_or(0) as usize).min(MAX_MARKERS);
+    // The cue points first: `(id, offset in samples)`.
+    let mut points = Vec::new();
+    for i in 0..count {
+        let Some(point) = cue.get(4usize.saturating_add(i.saturating_mul(24))..) else { break };
+        let (Some(id), Some(offset)) = (u32_at(point, 0), u32_at(point, 20)) else { break };
+        points.push((id, offset));
+    }
+    // Only the names and lengths of those ids are kept, so a hostile `adtl` list cannot grow them past the cue count,
+    // and each record is a lookup, not a scan.
+    let wanted: HashSet<u32> = points.iter().map(|(id, _)| *id).collect();
+    let mut names: HashMap<u32, String> = HashMap::new();
+    let mut lengths: HashMap<u32, u32> = HashMap::new();
+    let mut records = 0usize;
+    'lists: for (_, list) in chunks.iter().filter(|(id, b)| id == b"LIST" && b.get(0..4) == Some(b"adtl")) {
+        let mut at = 4usize;
+        while let Some(head) = list.get(at..at.saturating_add(8)) {
+            let (Ok(id), Some(size)) = (<[u8; 4]>::try_from(&head[..4]), u32_at(head, 4)) else { break };
+            let start = at.saturating_add(8);
+            let Some(end) = start.checked_add(size as usize) else { break };
+            let Some(body) = list.get(start..end) else { break };
+            records += 1;
+            if records > MAX_ADTL_RECORDS {
+                break 'lists;
+            }
+            if let Some(cue_id) = u32_at(body, 0).filter(|c| wanted.contains(c)) {
+                match &id {
+                    // A `labl` is the name; a `note` only when there is none.
+                    b"labl" => {
+                        names.insert(cue_id, label(body.get(4..).unwrap_or_default()));
+                    }
+                    b"note" => {
+                        names.entry(cue_id).or_insert_with(|| label(body.get(4..).unwrap_or_default()));
+                    }
+                    // The first `ltxt` of a cue point gives its length.
+                    b"ltxt" => {
+                        lengths.entry(cue_id).or_insert_with(|| u32_at(body, 4).unwrap_or(0));
+                    }
+                    _ => {}
+                }
+            }
+            at = end.saturating_add(end & 1);
+        }
+    }
+    points
+        .into_iter()
+        .map(|(id, offset)| {
+            let comment = names.get(&id).cloned().unwrap_or_default();
+            let length = lengths.get(&id).copied().unwrap_or(0);
+            Marker { time: secs(f64::from(offset), rate), duration: secs(f64::from(length), rate), comment, label: Label::None, ..Default::default() }
+        })
+        .collect()
+}
+
+/// The text of `name` in an XMP entry, as an attribute (`name="v"`) or an element
+/// (`<name>v</name>`).
+fn xmp_value(entry: &str, name: &str) -> Option<String> {
+    let attr = format!("{name}=\"");
+    if let Some(i) = entry.find(&attr) {
+        let rest = entry.get(i + attr.len()..)?;
+        return Some(unescape(rest.get(..rest.find('"')?)?));
+    }
+    let open = format!("<{name}>");
+    let i = entry.find(&open)?;
+    let rest = entry.get(i + open.len()..)?;
+    Some(unescape(rest.get(..rest.find('<')?)?))
+}
+
+fn unescape(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    let mut rest = s;
+    while let Some(i) = rest.find('&') {
+        out.push_str(rest.get(..i).unwrap_or_default());
+        let tail = rest.get(i..).unwrap_or_default();
+        let Some(semi) = tail.find(';').filter(|&n| n <= 10) else {
+            out.push('&');
+            rest = tail.get(1..).unwrap_or_default();
+            continue;
+        };
+        let ent = tail.get(1..semi).unwrap_or_default();
+        match ent {
+            "amp" => out.push('&'),
+            "lt" => out.push('<'),
+            "gt" => out.push('>'),
+            "quot" => out.push('"'),
+            "apos" => out.push('\''),
+            _ => {
+                let code = ent.strip_prefix("#x").and_then(|h| u32::from_str_radix(h, 16).ok()).or_else(|| ent.strip_prefix('#').and_then(|d| d.parse().ok()));
+                match code.and_then(char::from_u32) {
+                    Some(c) => out.push(c),
+                    None => out.push_str(tail.get(..=semi).unwrap_or_default()),
+                }
+            }
+        }
+        rest = tail.get(semi + 1..).unwrap_or_default();
+    }
+    out.push_str(rest);
+    out.trim().to_string()
+}
+
+/// A frame rate as XMP writes it: `f44100`, or `f30000s1001` (rate over scale).
+fn xmp_rate(text: &str) -> Option<f64> {
+    let t = text.trim().strip_prefix('f')?;
+    let (num, den) = t.split_once('s').unwrap_or((t, "1"));
+    let (n, d): (f64, f64) = (num.parse().ok()?, den.parse().ok()?);
+    (n > 0.0 && d > 0.0).then_some(n / d)
+}
+
+/// The markers of an XMP packet's `xmpDM:markers` entries.
+fn xmp_markers(packet: &[u8], file_rate: f64) -> Vec<Marker> {
+    let text = String::from_utf8_lossy(packet.get(..packet.len().min(MAX_XMP)).unwrap_or_default());
+    let mut out = Vec::new();
+    // The frame rate belongs to the track an entry follows.
+    let mut rate = file_rate;
+    for entry in text.split("<rdf:li").skip(1) {
+        if let Some(r) = xmp_value(entry, "xmpDM:frameRate").as_deref().and_then(xmp_rate) {
+            rate = r;
+        }
+        let Some(start) = xmp_value(entry, "xmpDM:startTime").and_then(|v| v.trim().parse::<f64>().ok()) else { continue };
+        let length = xmp_value(entry, "xmpDM:duration").and_then(|v| v.trim().parse::<f64>().ok()).unwrap_or(0.0);
+        let comment = xmp_value(entry, "xmpDM:name").unwrap_or_default();
+        out.push(Marker { time: secs(start, rate), duration: secs(length, rate), comment, label: Label::None, ..Default::default() });
+        if out.len() >= MAX_MARKERS {
+            break;
+        }
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn chunk(id: &[u8; 4], body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend((body.len() as u32).to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+
+    fn fmt(rate: u32) -> Vec<u8> {
+        let mut b = Vec::new();
+        b.extend(1u16.to_le_bytes()); // PCM
+        b.extend(1u16.to_le_bytes()); // mono
+        b.extend(rate.to_le_bytes());
+        b.extend((rate * 2).to_le_bytes());
+        b.extend(2u16.to_le_bytes());
+        b.extend(16u16.to_le_bytes());
+        chunk(b"fmt ", &b)
+    }
+
+    fn wav(chunks: &[Vec<u8>]) -> Vec<u8> {
+        let body: Vec<u8> = chunks.iter().flatten().copied().collect();
+        let mut v = b"RIFF".to_vec();
+        v.extend((body.len() as u32 + 4).to_le_bytes());
+        v.extend(b"WAVE");
+        v.extend(body);
+        v
+    }
+
+    fn cue(points: &[(u32, u32)]) -> Vec<u8> {
+        let mut b = (points.len() as u32).to_le_bytes().to_vec();
+        for (id, offset) in points {
+            b.extend(id.to_le_bytes());
+            b.extend(0u32.to_le_bytes());
+            b.extend(b"data");
+            b.extend(0u32.to_le_bytes());
+            b.extend(0u32.to_le_bytes());
+            b.extend(offset.to_le_bytes());
+        }
+        chunk(b"cue ", &b)
+    }
+
+    fn labl(id: &[u8; 4], cue_id: u32, text: &str) -> Vec<u8> {
+        let mut b = cue_id.to_le_bytes().to_vec();
+        b.extend(text.as_bytes());
+        b.push(0);
+        chunk(id, &b)
+    }
+
+    fn adtl(subs: &[Vec<u8>]) -> Vec<u8> {
+        let mut b = b"adtl".to_vec();
+        b.extend(subs.iter().flatten());
+        chunk(b"LIST", &b)
+    }
+
+    #[test]
+    fn cue_points_are_named_by_the_adtl_list_and_timed_in_samples() {
+        let file = wav(&[
+            fmt(44100),
+            chunk(b"data", &[0; 8]),
+            cue(&[(2, 88200), (1, 22050)]),
+            adtl(&[labl(b"labl", 1, "SEQ01_Prologue"), labl(b"labl", 2, "SEQ02_Vallee_P1_Agriculture")]),
+        ]);
+        let m = read(&file);
+        assert_eq!(m.len(), 2);
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("SEQ01_Prologue", Tick::from_seconds_f64(0.5)));
+        assert_eq!((m[1].comment.as_str(), m[1].time), ("SEQ02_Vallee_P1_Agriculture", Tick::from_seconds_f64(2.0)));
+    }
+
+    #[test]
+    fn a_note_names_a_cue_only_when_it_has_no_label_and_ltxt_gives_a_length() {
+        let mut ltxt = 1u32.to_le_bytes().to_vec();
+        ltxt.extend(44100u32.to_le_bytes());
+        ltxt.extend([0; 16]);
+        let file = wav(&[
+            fmt(44100),
+            cue(&[(1, 0), (2, 44100)]),
+            adtl(&[labl(b"note", 1, "from note"), chunk(b"ltxt", &ltxt), labl(b"labl", 2, "named"), labl(b"note", 2, "ignored")]),
+        ]);
+        let m = read(&file);
+        assert_eq!((m[0].comment.as_str(), m[0].duration), ("from note", Tick::from_seconds_f64(1.0)));
+        assert_eq!(m[1].comment, "named");
+    }
+
+    const XMP_ELEMENTS: &str = r#"<x:xmpmeta><rdf:RDF><rdf:Description><xmpDM:Tracks><rdf:Bag><rdf:li rdf:parseType="Resource"><xmpDM:trackName>Markers</xmpDM:trackName><xmpDM:trackType>Cue</xmpDM:trackType><xmpDM:frameRate>f44100</xmpDM:frameRate><xmpDM:markers><rdf:Seq><rdf:li rdf:parseType="Resource"><xmpDM:startTime>44100</xmpDM:startTime><xmpDM:duration>0</xmpDM:duration><xmpDM:name>One &amp; Two</xmpDM:name></rdf:li><rdf:li rdf:parseType="Resource"><xmpDM:startTime>132300</xmpDM:startTime><xmpDM:duration>22050</xmpDM:duration><xmpDM:name>Three</xmpDM:name></rdf:li></rdf:Seq></xmpDM:markers></rdf:li></rdf:Bag></xmpDM:Tracks></rdf:Description></rdf:RDF></x:xmpmeta>"#;
+
+    #[test]
+    fn xmp_markers_are_read_as_elements_in_frames_of_the_track_rate() {
+        let file = wav(&[fmt(48000), chunk(b"_PMX", XMP_ELEMENTS.as_bytes())]);
+        let m = read(&file);
+        assert_eq!(m.len(), 2);
+        // 44100 frames at f44100 is one second, whatever the file's own rate.
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("One & Two", Tick::from_seconds_f64(1.0)));
+        assert_eq!((m[1].comment.as_str(), m[1].time, m[1].duration), ("Three", Tick::from_seconds_f64(3.0), Tick::from_seconds_f64(0.5)));
+    }
+
+    #[test]
+    fn xmp_markers_are_read_as_attributes_and_use_the_file_rate_without_a_track_rate() {
+        let xmp = r#"<rdf:Seq><rdf:li xmpDM:startTime="24000" xmpDM:duration="0" xmpDM:name="Attr &#233;"/></rdf:Seq>"#;
+        let m = read(&wav(&[fmt(48000), chunk(b"_PMX", xmp.as_bytes())]));
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("Attr é", Tick::from_seconds_f64(0.5)));
+    }
+
+    #[test]
+    fn a_marker_in_both_encodings_is_listed_once() {
+        let xmp = r#"<rdf:li xmpDM:startTime="44100" xmpDM:name="Same"/><rdf:li xmpDM:startTime="88200" xmpDM:name="Only XMP"/>"#;
+        let file = wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Same")]), chunk(b"_PMX", xmp.as_bytes())]);
+        let names: Vec<String> = read(&file).into_iter().map(|m| m.comment).collect();
+        assert_eq!(names, ["Same", "Only XMP"]);
+    }
+
+    #[test]
+    fn importing_a_wav_puts_its_markers_on_the_footage() {
+        let file = wav(&[
+            fmt(44100),
+            chunk(b"data", &[0; 4 * 44100]),
+            cue(&[(1, 0), (2, 44100)]),
+            adtl(&[labl(b"labl", 1, "SEQ01_Prologue"), labl(b"labl", 2, "SEQ02_Vallee_P1_Agriculture")]),
+        ]);
+        let f = crate::probe::probe_bytes("markers.wav", file.into()).expect("probe");
+        assert!(f.has_audio);
+        let names: Vec<&str> = f.markers.iter().map(|m| m.comment.as_str()).collect();
+        assert_eq!(names, ["SEQ01_Prologue", "SEQ02_Vallee_P1_Agriculture"]);
+        assert_eq!(f.markers[1].time, Tick::from_seconds_f64(1.0));
+    }
+
+    #[test]
+    fn damaged_or_hostile_files_read_as_far_as_they_go_without_panicking() {
+        assert!(read(b"").is_empty());
+        assert!(read(b"RIFF").is_empty());
+        assert!(read(b"not a wav file at all").is_empty());
+        let good = wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Kept")])]);
+        // Every truncation is safe.
+        for n in 0..good.len() {
+            let _ = read(&good[..n]);
+        }
+        // A cue count far beyond the chunk, and chunk sizes past the end of the file.
+        let mut huge = 0xFFFF_FFFFu32.to_le_bytes().to_vec();
+        huge.extend([0; 24]);
+        let m = read(&wav(&[fmt(44100), chunk(b"cue ", &huge)]));
+        assert!(m.len() <= 1);
+        let mut lying = good.clone();
+        lying.extend(b"LIST\xff\xff\xff\xffadtl");
+        assert_eq!(read(&lying).len(), 1);
+        // No sample rate: times are zero, not a division by zero.
+        let m = read(&wav(&[cue(&[(1, 44100)])]));
+        assert_eq!(m[0].time, Tick::ZERO);
+    }
+
+    /// A chunk whose size field says `field` (an RF64 file's `0xFFFFFFFF`) while its body is `body`.
+    fn chunk_with_size_field(id: &[u8; 4], field: u32, body: &[u8]) -> Vec<u8> {
+        let mut v = id.to_vec();
+        v.extend(field.to_le_bytes());
+        v.extend(body);
+        if body.len() % 2 == 1 {
+            v.push(0);
+        }
+        v
+    }
+
+    /// An RF64 `ds64` chunk: the `data` chunk's size and a table of other chunks' sizes.
+    fn ds64_chunk(data_size: u64, table: &[([u8; 4], u64)]) -> Vec<u8> {
+        let mut b = 0u64.to_le_bytes().to_vec(); // riff size (not used)
+        b.extend(data_size.to_le_bytes());
+        b.extend(0u64.to_le_bytes()); // sample count
+        b.extend((table.len() as u32).to_le_bytes());
+        for (id, size) in table {
+            b.extend(id);
+            b.extend(size.to_le_bytes());
+        }
+        chunk(b"ds64", &b)
+    }
+
+    fn rf64(chunks: &[Vec<u8>]) -> Vec<u8> {
+        let body: Vec<u8> = chunks.iter().flatten().copied().collect();
+        let mut v = b"RF64".to_vec();
+        v.extend(u32::MAX.to_le_bytes());
+        v.extend(b"WAVE");
+        v.extend(body);
+        v
+    }
+
+    #[test]
+    fn rf64_markers_after_a_data_chunk_of_sentinel_size_are_read() {
+        let audio = [0u8; 8];
+        let file = rf64(&[
+            ds64_chunk(audio.len() as u64, &[]),
+            fmt(44100),
+            chunk_with_size_field(b"data", u32::MAX, &audio),
+            cue(&[(1, 44100)]),
+            adtl(&[labl(b"labl", 1, "After the audio")]),
+        ]);
+        let m = read(&file);
+        assert_eq!(m.len(), 1);
+        assert_eq!((m[0].comment.as_str(), m[0].time), ("After the audio", Tick::from_seconds_f64(1.0)));
+    }
+
+    #[test]
+    fn rf64_sizes_of_other_chunks_come_from_the_ds64_table() {
+        let junk = [7u8; 6];
+        let tail = || [cue(&[(1, 8000)]), adtl(&[labl(b"labl", 1, "Found")])].concat();
+        let with_entry = rf64(&[ds64_chunk(0, &[(*b"junk", junk.len() as u64)]), fmt(8000), chunk_with_size_field(b"junk", u32::MAX, &junk), tail()]);
+        assert_eq!(read(&with_entry)[0].comment, "Found");
+        // Without the table entry the sentinel is all there is, and what follows is not reached.
+        let without = rf64(&[ds64_chunk(0, &[]), fmt(8000), chunk_with_size_field(b"junk", u32::MAX, &junk), tail()]);
+        assert!(read(&without).is_empty());
+    }
+
+    #[test]
+    fn hostile_rf64_size_tables_read_as_far_as_they_go_without_panicking() {
+        // sizes that overflow when added to an offset
+        for data in [u64::MAX, u64::MAX - 7, 1 << 63] {
+            let file = rf64(&[ds64_chunk(data, &[(*b"junk", u64::MAX)]), fmt(8000), chunk_with_size_field(b"data", u32::MAX, &[0; 4]), cue(&[(1, 0)])]);
+            assert!(read(&file).is_empty());
+        }
+        // a table that claims far more entries than its chunk holds
+        let mut liar = ds64_chunk(0, &[]);
+        liar[8 + 24..8 + 28].copy_from_slice(&u32::MAX.to_le_bytes());
+        let _ = read(&rf64(&[liar, fmt(8000), cue(&[(1, 0)])]));
+        // every truncation of a good RF64 file is safe
+        let good =
+            rf64(&[ds64_chunk(4, &[]), fmt(44100), chunk_with_size_field(b"data", u32::MAX, &[0; 4]), cue(&[(1, 44100)]), adtl(&[labl(b"labl", 1, "Kept")])]);
+        assert_eq!(read(&good).len(), 1);
+        for n in 0..good.len() {
+            let _ = read(&good[..n]);
+        }
+    }
+
+    #[test]
+    fn a_huge_adtl_list_is_read_in_linear_time_and_only_for_the_cue_points_that_exist() {
+        // Records for ids that have no cue point are skipped, not stored, and the number looked at is capped.
+        let junk = |n: u32| (1000..1000 + n).map(|id| labl(b"labl", id, "n")).collect::<Vec<_>>();
+        let started = std::time::Instant::now();
+        // the real label comes first: read
+        let mut subs = vec![labl(b"labl", 1, "Real")];
+        subs.extend(junk(100_000));
+        let m = read(&wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&subs)]));
+        assert_eq!(m[0].comment, "Real");
+        // it comes after more records than are looked at: not read, and the marker is still there
+        let mut subs = junk(MAX_ADTL_RECORDS as u32 + 10);
+        subs.push(labl(b"labl", 1, "Too late"));
+        let m = read(&wav(&[fmt(44100), cue(&[(1, 44100)]), adtl(&subs)]));
+        assert_eq!((m.len(), m[0].comment.as_str()), (1, ""));
+        assert!(started.elapsed() < std::time::Duration::from_secs(5), "took {:?}", started.elapsed());
+    }
+}
diff --git a/crates/project/src/build.rs b/crates/project/src/build.rs
index b78e3d8c1..95ed262d4 100644
--- a/crates/project/src/build.rs
+++ b/crates/project/src/build.rs
@@ -881,6 +881,14 @@ pub fn layer(project: &mut Project, comp: &Comp, name: &str, source: LayerSource
             _ => {}
         }
     }
+    // A footage layer starts with the markers its file carries (layer time is footage time).
+    let footage_markers = match &source {
+        LayerSource::Footage { item } => match project.item(*item).map(|i| &i.kind) {
+            Some(crate::ItemKind::Footage(f)) => f.markers.clone(),
+            _ => vec![],
+        },
+        _ => vec![],
+    };
     let has_audio = matches!(&source, LayerSource::Footage { item } if matches!(project.item(*item).map(|i| &i.kind), Some(crate::ItemKind::Footage(f)) if f.has_audio))
         || matches!(source, LayerSource::Comp { .. });
     if has_audio {
@@ -910,7 +918,7 @@ pub fn layer(project: &mut Project, comp: &Comp, name: &str, source: LayerSource
         preserve_transparency: false,
         track_matte: None,
         parent: None,
-        markers: vec![],
+        markers: footage_markers,
         markers_locked: false,
         environment: false,
         environment_background: false,
diff --git a/crates/project/src/footage.rs b/crates/project/src/footage.rs
index 391b1e17c..486bc25f7 100644
--- a/crates/project/src/footage.rs
+++ b/crates/project/src/footage.rs
@@ -1,4 +1,4 @@
-use super::settings::yes;
+use super::settings::{Marker, yes};
 use super::{ColorSpace, Deserialize, FrameRate, Serialize, Tick};
 
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
@@ -115,6 +115,10 @@ pub struct Footage {
     /// timecode isn't read). It only relabels source time, as in After Effects.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub start_timecode: Option<i64>,
+    /// Markers the file carries (a WAV's cue points and XMP markers), at footage time. A layer
+    /// made from the footage starts with them, and Update Markers From Source copies new ones.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub markers: Vec<Marker>,
 }
 
 fn is_default<T: Default + PartialEq>(v: &T) -> bool {
@@ -150,6 +154,7 @@ impl Default for Footage {
             page: 0,
             alphabetical: false,
             start_timecode: None,
+            markers: vec![],
         }
     }
 }
diff --git a/crates/project/src/item.rs b/crates/project/src/item.rs
index 22759e27d..b2b64ed2c 100644
--- a/crates/project/src/item.rs
+++ b/crates/project/src/item.rs
@@ -267,10 +267,11 @@ impl Project {
     /// (NaN or infinity, written as `null`, and nesting too deep to parse) are refused on every
     /// save; debug builds also read the text back.
     pub fn to_file_json(&self) -> Result<String, ProjectError> {
-        self.to_file_json_with_view(&SavedView::default())
+        self.to_file_json_with_view(&SavedView::default(), false)
     }
-    /// [`Project::to_file_json`] that also records the open compositions ([`SavedView`]).
-    pub fn to_file_json_with_view(&self, view: &SavedView) -> Result<String, ProjectError> {
+    /// [`Project::to_file_json`] that also records the open compositions ([`SavedView`]), on one
+    /// line when `compact` (Settings ▸ Project ▸ Save Compact Project Files).
+    pub fn to_file_json_with_view(&self, view: &SavedView, compact: bool) -> Result<String, ProjectError> {
         if self.schema > SCHEMA_VERSION {
             return Err(ProjectError::Invalid(format!(
                 "the project can't be saved: it holds a value a project file can't store (project schema {} is newer than this version supports ({SCHEMA_VERSION}))",
@@ -289,7 +290,8 @@ impl Project {
         let file = File { saved_by: APP_VERSION, view, project: self };
         file_check::check(&file)
             .map_err(|e| ProjectError::Invalid(format!("the project can't be saved: it holds a value a project file can't store ({e})")))?;
-        let text = serde_json::to_string_pretty(&file).map_err(|e| ProjectError::Invalid(format!("the project can't be saved: {e}")))?;
+        let text = if compact { serde_json::to_string(&file) } else { serde_json::to_string_pretty(&file) }
+            .map_err(|e| ProjectError::Invalid(format!("the project can't be saved: {e}")))?;
         #[cfg(debug_assertions)]
         Project::from_json(&text)
             .map_err(|e| ProjectError::Invalid(format!("the project can't be saved: it holds a value a project file can't store ({e})")))?;
diff --git a/crates/project/src/render_queue.rs b/crates/project/src/render_queue.rs
index 777b7e289..1a829630c 100644
--- a/crates/project/src/render_queue.rs
+++ b/crates/project/src/render_queue.rs
@@ -442,9 +442,18 @@ impl RenderSettings {
     pub fn frame_time(&self, comp: &Comp, i: u64) -> Tick {
         self.rate(comp).tick_of(self.first_frame(comp) + i as i64)
     }
-    pub fn output_size(&self, comp: &Comp) -> (u32, u32) {
+    pub fn effective_scale(&self, comp: &Comp) -> f64 {
         let s = self.resolution.clamp(0.01, 4.0);
-        (((comp.width as f64 * s).round() as u32).max(1), ((comp.height as f64 * s).round() as u32).max(1))
+        let max = f64::from(crate::limits::MAX_SIZE);
+        s.min(max / f64::from(comp.width.max(1))).min(max / f64::from(comp.height.max(1)))
+    }
+    pub fn output_size(&self, comp: &Comp) -> (u32, u32) {
+        let s = self.effective_scale(comp);
+        // The scale is clamped so neither side exceeds the comp limit, keeping the aspect
+        // ratio: a 30 000 px side at 4x renders at 1x instead of cropping to a corner.
+        let w = ((comp.width as f64 * s).round() as u32).max(1);
+        let h = ((comp.height as f64 * s).round() as u32).max(1);
+        (w, h)
     }
     pub fn resolution_label(&self) -> &'static str {
         match self.resolution {
@@ -779,15 +788,18 @@ impl Crop {
         if self.use_roi
             && let Some([x, y, rw, rh]) = self.roi
         {
-            // The quad arrives unvalidated (control channel or a hand-edited project):
-            // clamp like the sibling edge fields (plus/minus 20 000) and subtract
-            // without overflow.
-            let conv = |v: f64| v.round().clamp(-20_000.0, 20_000.0) as i32;
-            let l = conv(x * scale);
-            let t = conv(y * scale);
-            let r = (w as i32).saturating_sub(conv((x + rw) * scale));
-            let b = (h as i32).saturating_sub(conv((y + rh) * scale));
-            return (t, l, b, r);
+            // The quad arrives unvalidated (control channel or a hand-edited project). As in
+            // After Effects, the region of interest lies inside the frame: each converted edge
+            // is clamped to [0, w] / [0, h] (inf clamps to a side, NaN converts to 0), and the
+            // far edge never passes the near one. Every edge then lies inside the frame, so the
+            // crop can't be larger than the frame and no subtraction can overflow.
+            let (wi, hi) = (i32::try_from(w).unwrap_or(i32::MAX), i32::try_from(h).unwrap_or(i32::MAX));
+            let conv = |v: f64, side: i32| v.round().clamp(0.0, f64::from(side)) as i32;
+            let l = conv(x * scale, wi);
+            let t = conv(y * scale, hi);
+            let r = conv((x + rw) * scale, wi).max(l);
+            let b = conv((y + rh) * scale, hi).max(t);
+            return (t, l, hi - b, wi - r);
         }
         (self.top, self.left, self.bottom, self.right)
     }
@@ -1126,7 +1138,7 @@ impl OutputModule {
     /// rounding).
     pub fn output_size(&self, comp: &Comp, settings: &RenderSettings) -> (u32, u32) {
         let (w, h) = settings.output_size(comp);
-        let (w, h) = self.frame_size(w, h, settings.resolution.clamp(0.01, 4.0));
+        let (w, h) = self.frame_size(w, h, settings.effective_scale(comp));
         self.format.coded_size(w, h)
     }
     /// Every setting as `(label, value)` lines (render logs).
@@ -1659,8 +1671,8 @@ mod tests {
 
     #[test]
     fn hostile_roi_cannot_overflow_crop_math() {
-        // `-1e12` saturates to `i32::MIN` on conversion: `w as i32 - l` must saturate,
-        // not overflow, and still yield a usable (degenerate) frame size.
+        // `-1e12` is clamped into the frame on conversion: it must not overflow and must still
+        // yield a usable (degenerate) frame size.
         let c = Comp::new(1920, 1080, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
         let rs = RenderSettings::default();
         let mut m = OutputModule::for_format(OutputFormat::PngSequence);
@@ -1673,6 +1685,66 @@ mod tests {
         assert_eq!(m.output_size(&c, &half), (400, 200));
     }
 
+    #[test]
+    fn output_size_never_exceeds_the_comp_limit() {
+        // The effective scale is clamped so neither side exceeds the limit (exporter
+        // `w * h * 4` would overflow at 120 000 px sides); the pipeline renders at the
+        // same scale, so it never requests a frame larger than this reports.
+        let rs = RenderSettings { resolution: 4.0, ..Default::default() };
+        let m = OutputModule::for_format(OutputFormat::PngSequence);
+        let square = Comp::new(30_000, 30_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(rs.effective_scale(&square), 1.0);
+        assert_eq!(rs.output_size(&square), (30_000, 30_000));
+        assert_eq!(m.output_size(&square, &rs), (30_000, 30_000));
+        // Wide comps keep their aspect ratio instead of clamping each side on its own.
+        let wide = Comp::new(30_000, 15_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(rs.effective_scale(&wide), 1.0);
+        assert_eq!(rs.output_size(&wide), (30_000, 15_000));
+        assert_eq!(m.output_size(&wide, &rs), (30_000, 15_000));
+        // A mid-size comp renders at the largest scale that still fits.
+        let mid = Comp::new(20_000, 10_000, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        assert_eq!(mid.width as f64 * rs.effective_scale(&mid), 30_000.0);
+        assert_eq!(rs.output_size(&mid), (30_000, 15_000));
+    }
+
+    #[test]
+    fn valid_wide_roi_endpoints_are_preserved() {
+        // A supported 30 000 x 100 frame at scale 1: ROI [10000, 0, 20000, 100] spans x 10 000..30 000
+        // and must give 20 000 x 100 (the absolute right edge 30 000 exceeds the old +/-20 000 clamp).
+        let c = Comp::new(30_000, 100, FrameRate::new(30, 1), Tick::from_seconds_f64(1.0));
+        let rs = RenderSettings::default();
+        let mut m = OutputModule::for_format(OutputFormat::PngSequence);
+        m.crop = Crop { enabled: true, use_roi: true, roi: Some([10_000.0, 0.0, 20_000.0, 100.0]), ..Default::default() };
+        assert_eq!(m.output_size(&c, &rs), (20_000, 100));
+        assert_eq!(m.crop.edges(30_000, 100, 1.0), (0, 10_000, 0, 0));
+        // Scale 4.0 pushes a valid edge to 120 000 px (30 000 x 4); the left edge 40 000 and the
+        // right edge 120 000 are both beyond 20 000 and must survive.
+        assert_eq!(m.crop.edges(120_000, 400, 4.0), (0, 40_000, 0, 0));
+        assert_eq!(m.frame_size(120_000, 400, 4.0), (80_000, 400));
+        // Hostile quads stay inside the frame: never empty, never larger than the frame, so the
+        // export can't be asked for an unbounded crop (an ROI reaching far outside the comp
+        // used to pad the frame instead).
+        let (fw, fh) = (1920, 1080);
+        let hostile = [
+            [1e300, 1e300, 1e300, 1e300],
+            [-1e300, -1e300, 1e300, 1e300],
+            [-1e6, -1e6, 2e6 + 1920.0, 2e6 + 1080.0],
+            [-1e12, -1e12, -1e12, -1e12],
+            [f64::NAN, f64::INFINITY, f64::NEG_INFINITY, f64::NAN],
+            [f64::NEG_INFINITY, f64::NEG_INFINITY, f64::INFINITY, f64::INFINITY],
+        ];
+        for roi in hostile {
+            m.crop.roi = Some(roi);
+            let (t, l, b, r) = m.crop.edges(fw, fh, 1.0);
+            assert!([t, l, b, r].iter().all(|e| *e >= 0), "{roi:?}: an edge pads the frame: {:?}", (t, l, b, r));
+            let (w, h) = m.frame_size(fw, fh, 1.0);
+            assert!((1..=fw).contains(&w) && (1..=fh).contains(&h), "{roi:?}: {w}x{h} is outside 1x1..={fw}x{fh}");
+        }
+        // An ROI covering more than the frame is the whole frame.
+        m.crop.roi = Some([-1e6, -1e6, 2e6 + 1920.0, 2e6 + 1080.0]);
+        assert_eq!(m.frame_size(fw, fh, 1.0), (fw, fh));
+    }
+
     #[test]
     fn uncompressed_quicktime_format() {
         let f = OutputFormat::from_name("uncompressed").unwrap();
diff --git a/crates/project/src/tests.rs b/crates/project/src/tests.rs
index f9ee16167..c0bdb012f 100644
--- a/crates/project/src/tests.rs
+++ b/crates/project/src/tests.rs
@@ -183,7 +183,7 @@ fn project_files_refuse_newer_schemas() {
         crate::SCHEMA_VERSION
     );
     assert_eq!(p.to_file_json().unwrap_err().to_string(), expected);
-    assert_eq!(p.to_file_json_with_view(&crate::SavedView::default()).unwrap_err().to_string(), expected);
+    assert_eq!(p.to_file_json_with_view(&crate::SavedView::default(), false).unwrap_err().to_string(), expected);
 }
 
 #[test]
@@ -197,7 +197,7 @@ fn saved_files_reopen_in_pretty_and_compact_form() {
 fn project_files_remember_the_open_comps() {
     let (p, cid) = project_with_layer();
     let view = crate::SavedView { active_comp: Some(cid), open_comps: vec![cid], comp_times: [(cid, effectcraft_time::Tick(4_237_833_600))].into() };
-    let text = p.to_file_json_with_view(&view).unwrap();
+    let text = p.to_file_json_with_view(&view, false).unwrap();
     assert_eq!(crate::saved_view(&text), view);
     assert_eq!(Project::from_json(&text).unwrap(), p, "the view is not part of the project");
     // Files from before #748 have no view; a garbled one is ignored, not an error.
diff --git a/crates/raster/src/lib.rs b/crates/raster/src/lib.rs
index 9f2e4e755..fd2fd183b 100644
--- a/crates/raster/src/lib.rs
+++ b/crates/raster/src/lib.rs
@@ -23,6 +23,11 @@ pub use warp::{Sampling, WarpOpts, accumulate_warp, composite_warp, composite_wa
 
 pub type Px = [f32; 4];
 
+/// Maximum padded side in pixels — mirrors the project crate's `limits::MAX_SIZE` (30 000;
+/// raster sits below it in the layering and may not depend on it, so the two must stay equal).
+/// A padded side beyond the largest supported comp side has no render use.
+pub const MAX_PADDED_SIDE: u32 = 30_000;
+
 /// Clamp (colour ≤ alpha ≤ 1, NaN → 0) and round half up to `levels` steps (`inv` = 1 / levels):
 /// one pixel of an 8/16 bpc buffer. Values are non-negative after the clamp, so the integer
 /// conversion rounds like `round()` and vectorises.
@@ -161,13 +166,28 @@ impl Image {
         }
         o
     }
-    /// Copy with `pad` transparent pixels on every side.
+    /// The pad [`Image::padded`] applies for a requested `pad`: clamped so neither output side
+    /// exceeds [`MAX_PADDED_SIDE`]. At most `(MAX_PADDED_SIDE - side) / 2`, so
+    /// `side + 2 · pad ≤ MAX_PADDED_SIDE` and overflow is unreachable by construction (a side
+    /// already past the cap gets pad 0). Callers that track where the pixels went (a buffer
+    /// offset) must move by this, not by the requested pad.
+    pub fn effective_pad(&self, pad: u32) -> u32 {
+        pad.min(MAX_PADDED_SIDE.saturating_sub(self.width) / 2).min(MAX_PADDED_SIDE.saturating_sub(self.height) / 2)
+    }
+    /// Copy with [`Image::effective_pad`] transparent pixels on every side.
+    ///
+    /// The clamp keeps the output within the largest image the engine supports (a max-size comp
+    /// frame), so an unbounded pad cannot overflow or size a buffer past that. It is not a memory
+    /// budget: callers that pad by a derived, possibly large amount bound the area themselves
+    /// (`DOF_PAD_BUDGET` in render's `three_d/compose.rs`, `fits()` on the GPU path) or reject an
+    /// oversized pad first (`padded_size`); legitimate bounded pads are byte-identical.
     pub fn padded(&self, pad: u32) -> Image {
-        let mut out = Image::new(self.width + 2 * pad, self.height + 2 * pad);
+        let eff = self.effective_pad(pad);
+        let mut out = Image::new(self.width + 2 * eff, self.height + 2 * eff);
         let ow = out.width as usize;
         for y in 0..self.height as usize {
             let src = &self.data[y * self.width as usize..(y + 1) * self.width as usize];
-            let o = (y + pad as usize) * ow + pad as usize;
+            let o = (y + eff as usize) * ow + eff as usize;
             out.data[o..o + self.width as usize].copy_from_slice(src);
         }
         out
@@ -222,7 +242,7 @@ impl Image {
     }
     /// Straight-alpha 8-bit RGBA (sRGB-encoded values as stored).
     pub fn to_rgba8(&self) -> Vec<u8> {
-        self.map_rgba8(|o, p| {
+        self.map_rgba8(|o, p, _, _| {
             let a = p[3].clamp(0.0, 1.0);
             let inv = if a > 0.0 { 1.0 / p[3] } else { 0.0 };
             for c in 0..3 {
@@ -231,9 +251,20 @@ impl Image {
             o[3] = (a * 255.0 + 0.5) as u8;
         })
     }
+    /// [`Image::to_rgba8`] with the colour dithered ([`dither_u8`]); alpha is rounded.
+    pub fn to_rgba8_dithered(&self) -> Vec<u8> {
+        self.map_rgba8(|o, p, x, y| {
+            let a = p[3].clamp(0.0, 1.0);
+            let inv = if a > 0.0 { 1.0 / p[3] } else { 0.0 };
+            for c in 0..3 {
+                o[c] = dither_u8(p[c] * inv, x, y);
+            }
+            o[3] = (a * 255.0 + 0.5) as u8;
+        })
+    }
     /// Composite over an opaque background colour and return opaque 8-bit RGBA.
     pub fn to_rgba8_over(&self, bg: [f32; 3]) -> Vec<u8> {
-        self.map_rgba8(|o, p| {
+        self.map_rgba8(|o, p, _, _| {
             let k = 1.0 - p[3].clamp(0.0, 1.0);
             for c in 0..3 {
                 o[c] = ((p[c] + bg[c] * k).clamp(0.0, 1.0) * 255.0 + 0.5) as u8;
@@ -241,13 +272,23 @@ impl Image {
             o[3] = 255;
         })
     }
-    /// 8-bit RGBA with each pixel written by `f`, row-parallel.
-    fn map_rgba8(&self, f: impl Fn(&mut [u8; 4], &Px) + Sync) -> Vec<u8> {
+    /// [`Image::to_rgba8_over`] with the colour dithered ([`dither_u8`]).
+    pub fn to_rgba8_over_dithered(&self, bg: [f32; 3]) -> Vec<u8> {
+        self.map_rgba8(|o, p, x, y| {
+            let k = 1.0 - p[3].clamp(0.0, 1.0);
+            for c in 0..3 {
+                o[c] = dither_u8(p[c] + bg[c] * k, x, y);
+            }
+            o[3] = 255;
+        })
+    }
+    /// 8-bit RGBA with each pixel written by `f` (given its x and y), row-parallel.
+    fn map_rgba8(&self, f: impl Fn(&mut [u8; 4], &Px, u32, u32) + Sync) -> Vec<u8> {
         let mut out = vec![0u8; self.data.len() * 4];
         let w = self.width.max(1) as usize;
-        out.par_chunks_mut(w * 4).zip(self.data.par_chunks(w)).for_each(|(o, row)| {
-            for (o, p) in o.as_chunks_mut::<4>().0.iter_mut().zip(row) {
-                f(o, p);
+        out.par_chunks_mut(w * 4).zip(self.data.par_chunks(w)).enumerate().for_each(|(y, (o, row))| {
+            for (x, (o, p)) in o.as_chunks_mut::<4>().0.iter_mut().zip(row).enumerate() {
+                f(o, p, x as u32, y as u32);
             }
         });
         out
@@ -322,6 +363,22 @@ pub fn hash_noise(x: u32, y: u32, seed: u32) -> f32 {
     (h & 0x00ff_ffff) as f32 / 16_777_216.0
 }
 
+/// Seed of the output dither: fixed, so a frame converts to the same bytes every time.
+const DITHER_SEED: u32 = 0x5bd1_e995;
+
+/// A colour value in 0..1 as an 8-bit code, dithered by pixel position (#2022): the value is
+/// scaled to 0..255 and rounded up or down against a per-pixel hash threshold, so the codes of
+/// a smooth gradient average to the gradient instead of stepping in bands. A value already on
+/// an 8-bit code (anything rendered at 8 bpc) comes out unchanged. Deterministic: depends only
+/// on the value and the pixel position, never on a clock or a global generator.
+#[inline]
+pub fn dither_u8(v: f32, x: u32, y: u32) -> u8 {
+    let s = v.clamp(0.0, 1.0) * 255.0;
+    // The threshold stays inside (1e-4, 1 - 1e-4) so float error on an exact code can't flip it.
+    let t = hash_noise(x, y, DITHER_SEED) * (1.0 - 2e-4) + 1e-4;
+    (s + t).floor() as u8
+}
+
 /// A single-channel coverage mask.
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct Mask {
@@ -346,6 +403,35 @@ impl Mask {
 mod tests {
     use super::*;
 
+    #[test]
+    fn dither_keeps_exact_codes_and_averages_the_rest() {
+        // A value on an 8-bit code is that code at every position.
+        for code in 0..=255u32 {
+            let v = code as f32 / 255.0;
+            for (x, y) in [(0, 0), (1, 0), (17, 3), (1919, 1079), (4095, 4095)] {
+                assert_eq!(dither_u8(v, x, y) as u32, code, "code {code} at ({x}, {y})");
+            }
+        }
+        // Out-of-range and NaN values saturate instead of wrapping.
+        assert_eq!((dither_u8(-3.0, 5, 5), dither_u8(7.0, 5, 5), dither_u8(f32::NAN, 5, 5)), (0, 255, 0));
+        // A value between two codes lands on both, in proportion: the mean over a block is the value.
+        let v = (100.0 + 0.3) / 255.0;
+        let n = 64u32;
+        let sum: u32 = (0..n * n).map(|i| dither_u8(v, i % n, i / n) as u32).sum();
+        let mean = sum as f32 / (n * n) as f32;
+        assert!((mean - 100.3).abs() < 0.03, "{mean}");
+        // Deterministic.
+        assert_eq!(dither_u8(v, 9, 4), dither_u8(v, 9, 4));
+    }
+
+    #[test]
+    fn dithered_conversions_match_the_plain_ones_on_exact_codes() {
+        let src: Vec<u8> = vec![255, 128, 0, 255, 10, 20, 30, 255, 0, 0, 0, 255, 1, 2, 3, 255];
+        let img = Image::from_rgba8(2, 2, &src);
+        assert_eq!(img.to_rgba8_dithered(), img.to_rgba8());
+        assert_eq!(img.to_rgba8_over_dithered([0.0; 3]), img.to_rgba8_over([0.0; 3]));
+    }
+
     #[test]
     fn rgba8_roundtrip() {
         let src: Vec<u8> = vec![255, 128, 0, 255, 10, 20, 30, 128, 0, 0, 0, 0, 1, 2, 3, 4];
@@ -384,4 +470,29 @@ mod tests {
             assert!((0.0..1.0).contains(&n));
         }
     }
+
+    #[test]
+    fn padded_bounds_hostile_pad_at_the_api() {
+        // Fail-before (#2092 class): before the clamp, a caller passing a hostile pad sized an
+        // oversized buffer here — the very OOM this guard exists to stop, now caught in padded().
+        // (Wide-flat source so the clamped-to-cap output stays a test-sized allocation.)
+        let mut img = Image::new(29_990, 2);
+        img.set(29_989, 1, [1.0, 0.0, 0.0, 1.0]);
+        let out = img.padded(u32::MAX);
+        // Width binds first: eff = (MAX_PADDED_SIDE - 29 990) / 2 = 5.
+        assert_eq!((out.width, out.height), (MAX_PADDED_SIDE, 12));
+        // The source lands intact at the clamped offset, not the requested one.
+        assert_eq!(out.get(29_994, 6), [1.0, 0.0, 0.0, 1.0]);
+        assert_eq!(out.get(0, 0), [0.0; 4]); // clamped pad region stays transparent
+    }
+
+    #[test]
+    fn padded_leaves_legit_pads_untouched() {
+        // Anti-over-clamp: an ordinary pad must round exactly, byte for byte.
+        let mut img = Image::new(8, 6);
+        img.set(3, 2, [1.0, 0.0, 0.0, 1.0]);
+        let out = img.padded(4);
+        assert_eq!((out.width, out.height), (16, 14));
+        assert_eq!(out.get(7, 6), [1.0, 0.0, 0.0, 1.0]); // (3+4, 2+4)
+    }
 }
diff --git a/crates/render/src/accel.rs b/crates/render/src/accel.rs
index accc1fc54..4f93e41d7 100644
--- a/crates/render/src/accel.rs
+++ b/crates/render/src/accel.rs
@@ -184,8 +184,9 @@ impl<'a> Renderer<'a> {
     pub fn layer_aux(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Arc<effectcraft_raster::AuxChannels>> {
         match &layer.source {
             LayerSource::Footage { item } => {
-                let ItemKind::Footage(f) = &self.project.item(*item)?.kind else { return None };
-                let a = self.footage.aux(*item, f, ctx.source_time(layer))?;
+                let item = ctx.media_item(layer, *item);
+                let ItemKind::Footage(f) = &self.project.item(item)?.kind else { return None };
+                let a = self.footage.aux(item, f, ctx.source_time(layer))?;
                 // Aux pixels per layer pixel (the layer is the footage at its nominal size). The
                 // planes are only copied when that changes the scale.
                 let scale = a.width as f64 / f.width as f64;
@@ -332,8 +333,8 @@ impl<'a> Renderer<'a> {
     }
 
     /// Draw a collapsed precomp layer into `canvas` on the CPU.
-    pub fn draw_collapsed_cpu(&self, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut Image) {
-        self.draw_collapsed(ctx, layer, item, canvas, false);
+    pub fn draw_collapsed_cpu(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &crate::Collapsed, canvas: &mut Image) {
+        self.draw_collapsed(ctx, layer, collapsed, canvas, false);
     }
 
     /// The layer's finished buffers (styles included) in the blending space.
diff --git a/crates/render/src/audio.rs b/crates/render/src/audio.rs
index 66b54b6d0..ee19d8b25 100644
--- a/crates/render/src/audio.rs
+++ b/crates/render/src/audio.rs
@@ -4,10 +4,13 @@
 //! (Effect > Audio, see [`effectcraft_effects::audio_fx`]) run on each layer's audio before
 //! its levels; Backwards plays the layer's [in, out) span reversed.
 //!
-//! Callers mix in short blocks (one video frame, or an audio device buffer). Effects and levels
-//! are evaluated once per block. To make the result independent of block boundaries, layer
-//! effects are run from a cleared state over a pre-roll of earlier audio and only the block's
-//! tail is kept — so preview playback and export produce identical samples.
+//! Callers mix in short blocks (one video frame, an audio device buffer, or a second of export).
+//! Effect parameters are evaluated once per block. Animated Audio Levels, and animated effects
+//! that work sample by sample (Stereo Mixer), are evaluated on a grid of comp samples every
+//! millisecond instead, so keyframed fades ramp smoothly whatever the block size. To make the
+//! result independent of block boundaries, layer effects are run from a cleared state over a
+//! pre-roll of earlier audio and only the block's tail is kept — so preview playback and export
+//! produce identical samples.
 //!
 //! Time-stretched layers are resampled nearest-sample; reversed (negative stretch) layers are
 //! silent for now.
@@ -85,6 +88,20 @@ fn units_ceil(t: Tick, rate: u32) -> i64 {
     (n.div_euclid(d) + i128::from(n.rem_euclid(d) != 0)) as i64
 }
 
+/// Samples between evaluations of animated levels and per-sample effects: one millisecond, on
+/// a grid of comp sample indices so the result does not depend on where a block starts.
+fn param_step(rate: u32) -> i64 {
+    i64::from(rate / 1000).max(1)
+}
+
+/// Does any property of the group change over time?
+fn animated(g: &effectcraft_project::PropGroup) -> bool {
+    g.children.iter().any(|c| match c {
+        Node::Prop(p) => p.is_animated() || p.has_expression(),
+        Node::Group(sub) => animated(sub),
+    })
+}
+
 fn sample_tick(i: i64, rate: u32) -> Tick {
     // Keep the requested sample when the rate does not divide the tick clock.
     let t = Tick::from_units(i, i64::from(rate));
@@ -189,21 +206,70 @@ impl MixEnv<'_> {
     /// `i0 .. i0 + n`.
     fn layer_audio(&self, l: &Layer, i0: i64, n: usize) -> Vec<f32> {
         let t = sample_tick(i0, self.rate);
-        let fx: Vec<(&str, Params)> = audio_effect_groups(l).map(|(id, g)| (id, self.params(l, g, t))).collect();
+        let fx: Vec<(&str, &effectcraft_project::PropGroup, Params)> = audio_effect_groups(l).map(|(id, g)| (id, g, self.params(l, g, t))).collect();
         if fx.is_empty() {
             return self.layer_raw(l, i0, n, false);
         }
-        let reversed = fx.iter().any(|(id, _)| audio_fx::reverses(id));
-        let pre_s: f64 = fx.iter().map(|(id, p)| audio_fx::preroll(id, p)).sum();
+        let reversed = fx.iter().any(|(id, _, _)| audio_fx::reverses(id));
+        let pre_s: f64 = fx.iter().map(|(id, _, p)| audio_fx::preroll(id, p)).sum();
         let pre = (pre_s * self.rate as f64).ceil() as usize;
-        let mut buf = self.layer_raw(l, i0 - pre as i64, n + pre, reversed);
-        let start = l.layer_time(sample_tick(i0 - pre as i64, self.rate)).seconds();
-        for (id, p) in &fx {
-            audio_fx::process(id, p, &mut buf, self.rate, start);
+        let b0 = i0 - pre as i64;
+        let mut buf = self.layer_raw(l, b0, n + pre, reversed);
+        let start = l.layer_time(sample_tick(b0, self.rate)).seconds();
+        for (id, g, p) in &fx {
+            if audio_fx::per_sample(id) && animated(g) {
+                self.process_stepped(l, id, g, &mut buf, b0);
+            } else {
+                audio_fx::process(id, p, &mut buf, self.rate, start);
+            }
         }
         buf.drain(..pre * 2);
         buf
     }
+
+    /// Run per-sample effect `id` over `buf` (comp samples from `b0`) in pieces of the parameter
+    /// grid, each with the parameters at its first sample.
+    fn process_stepped(&self, l: &Layer, id: &str, g: &effectcraft_project::PropGroup, buf: &mut [f32], b0: i64) {
+        let step = param_step(self.rate);
+        let frames = buf.len() / 2;
+        let mut k = 0usize;
+        while k < frames {
+            let i = b0.saturating_add(k as i64);
+            let next = i.div_euclid(step).saturating_add(1).saturating_mul(step);
+            let end = usize::try_from(next.saturating_sub(b0)).unwrap_or(frames).clamp(k + 1, frames);
+            let t = sample_tick(i, self.rate);
+            if let Some(piece) = buf.get_mut(k * 2..end * 2) {
+                audio_fx::process(id, &self.params(l, g, t), piece, self.rate, l.layer_time(t).seconds());
+            }
+            k = end;
+        }
+    }
+
+    /// Linear gains (left, right) of the layer's Audio Levels for comp samples `i0 .. i0 + n`.
+    /// Animated levels are evaluated on the parameter grid and interpolated in dB in between.
+    fn level_gains(&self, l: &Layer, i0: i64, n: usize) -> Vec<[f32; 2]> {
+        let Some(pr) = l.props.sub("audio").and_then(|g| g.get("levels")) else { return vec![[1.0, 1.0]; n] };
+        let db = |i: i64| self.ctx(sample_tick(i, self.rate)).value(l, pr).as_vec2();
+        let gain = |[a, b]: [f64; 2]| [db_to_gain(a), db_to_gain(b)];
+        if !pr.is_animated() && !pr.has_expression() {
+            return vec![gain(db(i0)); n];
+        }
+        let step = param_step(self.rate);
+        let end = i0.saturating_add(n as i64);
+        let mut out = Vec::with_capacity(n);
+        let mut k = i0.div_euclid(step).saturating_mul(step);
+        let mut lo = db(k);
+        while k < end {
+            let hi = db(k.saturating_add(step));
+            for i in k.max(i0)..k.saturating_add(step).min(end) {
+                let f = (i - k) as f64 / step as f64;
+                out.push(gain([lo[0] + (hi[0] - lo[0]) * f, lo[1] + (hi[1] - lo[1]) * f]));
+            }
+            k = k.saturating_add(step);
+            lo = hi;
+        }
+        out
+    }
 }
 
 /// Shared inputs for composition audio mixing, including nested compositions.
@@ -234,25 +300,18 @@ fn mix_into(sources: &AudioSources<'_>, comp_id: ItemId, start: Tick, out: &mut
         if a >= b {
             continue;
         }
-        let t_a = sample_tick(s0 + a as i64, rate);
-        let (ll, lr) = levels(&env, l, t_a);
-        if ll == 0.0 && lr == 0.0 {
+        let gains = env.level_gains(l, s0 + a as i64, b - a);
+        if gains.iter().all(|g| *g == [0.0, 0.0]) {
             continue;
         }
         let buf = env.layer_audio(l, s0 + a as i64, b - a);
-        for (i, f) in buf.as_chunks::<2>().0.iter().enumerate() {
-            out[(a + i) * 2] += f[0] * ll;
-            out[(a + i) * 2 + 1] += f[1] * lr;
+        for (i, (f, g)) in buf.as_chunks::<2>().0.iter().zip(&gains).enumerate() {
+            out[(a + i) * 2] += f[0] * g[0];
+            out[(a + i) * 2 + 1] += f[1] * g[1];
         }
     }
 }
 
-fn levels(env: &MixEnv, l: &Layer, t: Tick) -> (f32, f32) {
-    let Some(g) = l.props.sub("audio") else { return (1.0, 1.0) };
-    let [a, b] = env.ctx(t).v2(l, g, "levels", [0.0, 0.0]);
-    (db_to_gain(a), db_to_gain(b))
-}
-
 /// A min/max peak summary of interleaved stereo audio for waveform drawing: one entry per
 /// `bin` sample frames, `[min L, max L, min R, max R]`.
 pub fn peak_summary(samples: &[f32], bin: usize) -> Vec<[f32; 4]> {
diff --git a/crates/render/src/cache.rs b/crates/render/src/cache.rs
index 28d2a8a89..1c7aadc55 100644
--- a/crates/render/src/cache.rs
+++ b/crates/render/src/cache.rs
@@ -479,6 +479,19 @@ fn group_has(g: &PropGroup, match_id: &str) -> bool {
 
 /// Feed every property of `g` that can change over time (keyframes or expression) as its value
 /// at the context time. The static structure is hashed separately.
+/// Mix the collapsed-instance overrides that target `id` into a cache key. They replace values
+/// without editing the layer, so a key without them would reuse another instance's buffer.
+fn hash_overrides(h: &mut KeyHasher, ctx: &EvalCtx, id: effectcraft_project::LayerId) {
+    for o in ctx.property_overrides.iter().filter(|o| o.layer == id) {
+        o.prop.hash(h);
+        o.font.hash(h);
+        hash_debug(h, &o.value);
+    }
+    for m in ctx.media_overrides.iter().filter(|m| m.layer == id) {
+        m.item.hash(h);
+    }
+}
+
 fn hash_values(h: &mut KeyHasher, ctx: &EvalCtx, layer: &Layer, g: &PropGroup) {
     for c in &g.children {
         match c {
@@ -605,8 +618,9 @@ fn key_any(ctx: &EvalCtx, layer: &Layer, scale: f64, draft: bool, blur: bool, fo
             hash_debug(&mut h, s);
         }
         LayerSource::Text | LayerSource::Shape => {}
-        LayerSource::Footage { item } if footage || still_footage(ctx, *item) => {
-            let it = ctx.project.item(*item)?;
+        LayerSource::Footage { item } if footage || still_footage(ctx, ctx.media_item(layer, *item)) => {
+            let item = ctx.media_item(layer, *item);
+            let it = ctx.project.item(item)?;
             let ItemKind::Footage(f) = &it.kind else { return None };
             hash_debug(&mut h, f);
             // A proxy (and its Use Proxy switch) changes the pixels.
@@ -629,6 +643,10 @@ fn key_any(ctx: &EvalCtx, layer: &Layer, scale: f64, draft: bool, blur: bool, fo
     scale.to_bits().hash(&mut h);
     draft.hash(&mut h);
     layer.id.hash(&mut h);
+    // Collapsed-instance overrides replace values without editing the nested layer, so mix them
+    // into the key: a Font override, effect parameter or any other source-affecting override
+    // must not reuse another instance's processed buffer.
+    hash_overrides(&mut h, ctx, layer.id);
     hash_debug(&mut h, &layer.source);
     // (Audio, Lock and Shy don't change pixels.)
     hash_debug(&mut h, &layer.switches.pixels());
diff --git a/crates/render/src/cache/dependencies.rs b/crates/render/src/cache/dependencies.rs
index 5deffa4db..1a550f9c7 100644
--- a/crates/render/src/cache/dependencies.rs
+++ b/crates/render/src/cache/dependencies.rs
@@ -3,7 +3,7 @@
 //! cyclic/over-budget graphs or expressions sampled at unknown times.
 use super::{KeyHasher, hash_debug, hash_values};
 use crate::EvalCtx;
-use effectcraft_project::{ItemId, ItemKind, Layer, LayerId, LayerSource, Node, PropGroup};
+use effectcraft_project::{ItemId, ItemKind, Layer, LayerId, LayerSource, LightKind, Node, PropGroup};
 use std::hash::Hash;
 
 pub(super) fn hash(h: &mut KeyHasher, ctx: &EvalCtx, layer: &Layer, effects: Option<usize>) -> Option<()> {
@@ -63,11 +63,68 @@ impl Dependencies<'_> {
         Some(())
     }
 
+    /// What a referenced 3D model or primitive layer's solo render depends on: the layer itself
+    /// (geometry, materials, switches, in/out), its animated values and transform at the time,
+    /// the mesh item, the comp's camera (with its depth of field) and its lights at the time
+    /// (the lights are off in draft 3D, and the renderer setting changes the pixels), the model's
+    /// layer time while it plays an animation clip, and the in/out gate (outside the range the
+    /// read is transparent). An Environment light's image can be any layer's render: with one on
+    /// the read is not cached. Comp size and render scale are in the owner's key already.
+    fn soloed_model(&mut self, ctx: &EvalCtx, layer: &Layer) -> Option<()> {
+        self.remaining = self.remaining.checked_sub(1)?;
+        // Expressions sampled at other times: not cacheable, as in the ordinary path.
+        if (self.other_times || super::reads_other_times(layer, None)) && super::has_expression(&layer.props) {
+            return None;
+        }
+        hash_debug(self.h, layer);
+        hash_values(self.h, ctx, layer, &layer.props);
+        hash_debug(self.h, &ctx.world_matrix(layer));
+        if let Some(item) = layer.source.item() {
+            hash_debug(self.h, &ctx.project.item(item));
+        }
+        // The solo render goes through the comp's camera and lights. The camera's depth of
+        // field blurs it (focus, aperture, iris, highlights) — none of that is in the
+        // projection hashed above.
+        hash_debug(self.h, &ctx.camera());
+        hash_debug(self.h, &crate::three_d::active_camera(ctx).dof);
+        hash_debug(self.h, &crate::three_d::light::lights_at(ctx));
+        hash_debug(self.h, &ctx.comp.draft_3d);
+        hash_debug(self.h, &ctx.comp.renderer);
+        // An Environment light's image lights Advanced 3D models (its source can be any
+        // layer's render, or any environment layer) — too open-ended to hash: while one is
+        // on (and lighting: Draft 3D lights nothing), don't cache the read.
+        if ctx.comp.renderer == effectcraft_project::Renderer::Advanced3D
+            && !ctx.comp.draft_3d
+            && ctx.comp.layers.iter().any(|l| {
+                l.is_light() && l.switches.video && l.is_active_at(ctx.time) && matches!(l.source, LayerSource::Light { kind: LightKind::Environment })
+            })
+        {
+            return None;
+        }
+        // A model with an animation clip selected is posed at its layer time (Animation Speed
+        // and Looping are static, hashed above): every time is its own entry. Without one the
+        // pose is the same at every time: keep the static key.
+        if layer.props.sub("geometryOptions").map_or(0, |g| ctx.e(layer, g, "animation")) != 0 {
+            layer.layer_time(ctx.time).0.hash(self.h);
+        }
+        // Outside the layer's in/out range the read is transparent: fold the gate in, so a
+        // static model renders once inside it and again when it leaves.
+        layer.is_active_at(ctx.time).hash(self.h);
+        Some(())
+    }
+
     fn layer(&mut self, ctx: &EvalCtx, layer: &Layer) -> Option<()> {
         let id = (ctx.comp_id, layer.id);
         if self.path.len() > crate::MAX_FX_DEPTH || self.path.contains(&id) {
             return None;
         }
+        // A referenced 3D model or primitive layer renders through the comp's camera and lights
+        // (an effect layer parameter reads it that way — Create 3D Layer Instance): hash what
+        // moves its pixels, so the owner keeps a cache entry that changes when any of it does.
+        if layer.source.is_model() {
+            self.soloed_model(ctx, layer)?;
+            return Some(());
+        }
         self.remaining = self.remaining.checked_sub(1)?;
         if (self.other_times || super::reads_other_times(layer, None)) && super::has_expression(&layer.props) {
             return None;
@@ -76,6 +133,9 @@ impl Dependencies<'_> {
         // Include transforms/parents as well as pixels: selected-layer anchors and
         // continuously rasterized sources can depend on them.
         hash_debug(self.h, layer);
+        // A referenced layer's static values can be overridden by the collapsed instance without
+        // editing it (`hash_values` only sees animated ones), so the owner's key needs them too.
+        super::hash_overrides(self.h, ctx, layer.id);
         hash_values(self.h, ctx, layer, &layer.props);
         hash_debug(self.h, &ctx.world_matrix(layer));
         // A cached owner never runs this layer's effects, so the comp camera and lights its
@@ -88,6 +148,10 @@ impl Dependencies<'_> {
         }
         match layer.source {
             LayerSource::Solid { item } | LayerSource::Footage { item } | LayerSource::Comp { item } => {
+                let item = match layer.source {
+                    LayerSource::Footage { .. } => ctx.media_item(layer, item),
+                    _ => item,
+                };
                 let source = ctx.project.item(item);
                 hash_debug(self.h, &source);
                 if let Some(source) = source {
diff --git a/crates/render/src/eval.rs b/crates/render/src/eval.rs
index 14249900f..81fe45d6c 100644
--- a/crates/render/src/eval.rs
+++ b/crates/render/src/eval.rs
@@ -39,17 +39,33 @@ pub struct EvalCtx<'a> {
     /// Footage frames for expressions that read rendered pixels (`sampleImage`): the renderer's
     /// own source while rendering; `None` renders footage as transparent.
     pub footage: Option<&'a dyn crate::FootageSource>,
+    /// Property values overridden by the Essential Properties of a collapsed precomp instance.
+    pub property_overrides: &'a [crate::PropertyOverride],
+    /// Media Replacement values overridden by the Essential Properties of a collapsed precomp
+    /// instance.
+    pub media_overrides: &'a [crate::MediaOverride],
 }
 
 impl<'a> EvalCtx<'a> {
     pub fn new(project: &'a Project, comp_id: ItemId, comp: &'a Comp, time: Tick) -> EvalCtx<'a> {
-        EvalCtx { project, comp_id, comp, time, expr: None, footage: None }
+        EvalCtx { project, comp_id, comp, time, expr: None, footage: None, property_overrides: &[], media_overrides: &[] }
     }
     pub fn at(&self, time: Tick) -> EvalCtx<'a> {
         EvalCtx { time, ..*self }
     }
     /// Value of a property at the context time (keyframes, then expression).
     pub fn value(&self, layer: &Layer, prop: &Property) -> Value {
+        // A collapsed precomp instance's Essential Property override replaces the base value;
+        // its expression (if any) still runs, and sees the overrides of this context.
+        if let Some(o) = self.property_overrides.iter().rev().find(|o| o.layer == layer.id && o.prop == prop.uid) {
+            let v = o.value(layer, prop, self.time);
+            if prop.has_expression()
+                && let Some(h) = self.expr
+            {
+                return h.eval(self, layer, prop, &v).unwrap_or(v);
+            }
+            return v;
+        }
         // Separated Position reads as the combination of X/Y/Z Position.
         if prop.match_id == "position"
             && let Some(tr) = layer.transform()
@@ -145,13 +161,15 @@ impl<'a> EvalCtx<'a> {
     /// Source pixel aspect relative to the comp's: non-square footage (or solids, or precomps
     /// with another pixel aspect) is stretched horizontally by this factor in the comp.
     pub fn par_ratio(&self, layer: &Layer) -> f64 {
-        let par = match &layer.source {
-            LayerSource::Footage { item } | LayerSource::Solid { item } | LayerSource::Comp { item } => match self.project.item(*item).map(|i| &i.kind) {
-                Some(effectcraft_project::ItemKind::Footage(f)) => f.pixel_aspect,
-                Some(effectcraft_project::ItemKind::Solid(s)) => s.pixel_aspect,
-                Some(effectcraft_project::ItemKind::Comp(c)) => c.pixel_aspect,
-                _ => 1.0,
-            },
+        let item = match &layer.source {
+            LayerSource::Footage { item } => Some(self.media_item(layer, *item)),
+            LayerSource::Solid { item } | LayerSource::Comp { item } => Some(*item),
+            _ => None,
+        };
+        let par = match item.and_then(|item| self.project.item(item)).map(|i| &i.kind) {
+            Some(effectcraft_project::ItemKind::Footage(f)) => f.pixel_aspect,
+            Some(effectcraft_project::ItemKind::Solid(s)) => s.pixel_aspect,
+            Some(effectcraft_project::ItemKind::Comp(c)) => c.pixel_aspect,
             _ => 1.0,
         };
         let r = par / if self.comp.pixel_aspect > 0.0 { self.comp.pixel_aspect } else { 1.0 };
@@ -237,9 +255,27 @@ impl<'a> EvalCtx<'a> {
             (Mat3([[m[0][0], m[0][1], m[0][3]], [m[1][0], m[1][1], m[1][3]], [0.0, 0.0, 1.0]]), 0.0)
         }
     }
+    /// The footage item a layer uses, honouring this instance's Media Replacement override.
+    pub fn media_item(&self, layer: &Layer, item: ItemId) -> ItemId {
+        self.media_overrides.iter().rev().find(|m| m.layer == layer.id).map_or(item, |m| m.item)
+    }
+
+    /// Size of a layer's source in layer pixels, honouring Media Replacement.
+    pub fn source_size(&self, layer: &Layer) -> (u32, u32) {
+        let item = match &layer.source {
+            LayerSource::Footage { item } => Some(self.media_item(layer, *item)),
+            LayerSource::Comp { item } | LayerSource::Solid { item } => Some(*item),
+            _ => None,
+        };
+        match layer.source {
+            LayerSource::Null => (100, 100),
+            _ => item.and_then(|item| self.project.item(item)).and_then(|i| i.dimensions()).unwrap_or((0, 0)),
+        }
+    }
+
     /// [`effect_bounds`] of a layer of this comp.
     pub fn effect_bounds(&self, layer: &Layer) -> ([f64; 2], [f64; 2]) {
-        effect_bounds(self.project, self.comp, layer)
+        effect_bounds_of(self.comp, self.source_size(layer))
     }
     /// Effect space (see [`effect_bounds`]) → comp matrix.
     pub fn effect_to_comp(&self, layer: &Layer) -> Mat3 {
@@ -248,6 +284,20 @@ impl<'a> EvalCtx<'a> {
     }
 }
 
+impl crate::PropertyOverride {
+    fn value(&self, layer: &Layer, prop: &Property, time: Tick) -> Value {
+        if self.font {
+            // A Font control merges only the font into the target text, as
+            // `essential::with_overrides` does.
+            let mut value = prop.value_at(layer.layer_time(time));
+            effectcraft_project::essential::merge_font(&mut value, &self.value);
+            value
+        } else {
+            self.value.clone()
+        }
+    }
+}
+
 /// The protected regions of a comp (Responsive Design — Time markers), merged, sorted and
 /// clamped to the comp, in seconds.
 pub fn protected_regions(comp: &Comp) -> Vec<(f64, f64)> {
@@ -321,7 +371,11 @@ pub fn responsive_source_time(comp: &Comp, stretch: f64, elapsed: f64) -> Option
 /// surrounds. Effects work in **effect space**, measured from that corner (After Effects' layer
 /// space for effect points: a shape layer's default effect point is its bounds' centre).
 pub fn effect_bounds(project: &Project, comp: &Comp, layer: &Layer) -> ([f64; 2], [f64; 2]) {
-    match source_size(project, layer) {
+    effect_bounds_of(comp, source_size(project, layer))
+}
+
+fn effect_bounds_of(comp: &Comp, size: (u32, u32)) -> ([f64; 2], [f64; 2]) {
+    match size {
         (0, _) => {
             let (w, h) = (comp.width as f64, comp.height as f64);
             ([w, h], [-w / 2.0, -h / 2.0])
diff --git a/crates/render/src/frames.rs b/crates/render/src/frames.rs
index 7dd0fc0de..3024dfc52 100644
--- a/crates/render/src/frames.rs
+++ b/crates/render/src/frames.rs
@@ -1,6 +1,6 @@
 use super::footage::NoFootage;
 use super::opts::RenderOpts;
-use super::{EvalCtx, Footage, FrameBlend, FrameRate, Image, ItemId, Layer, LayerSource, Project, Renderer, TICKS_PER_SECOND, Tick, shapes, source_size, text};
+use super::{EvalCtx, Footage, FrameBlend, FrameRate, Image, ItemId, Layer, LayerSource, Project, Renderer, TICKS_PER_SECOND, Tick, shapes, text};
 
 /// The layer's frame blending mode, if the comp's Enable Frame Blending switch is on.
 /// One field of an interlaced frame as a full frame: the field's lines (`parity` 0 = even /
@@ -132,7 +132,7 @@ pub fn content_bounds(ctx: &EvalCtx, layer: &effectcraft_project::Layer) -> Opti
         LayerSource::Shape => layer.props.sub("contents").and_then(|c| shapes::content_bounds(ctx, layer, c)).map(|r| [r.x0, r.y0, r.x1, r.y1]),
         LayerSource::Camera | LayerSource::Light { .. } => None,
         _ => {
-            let (w, h) = source_size(ctx.project, layer);
+            let (w, h) = ctx.source_size(layer);
             (w > 0 && h > 0).then_some([0.0, 0.0, w as f64, h as f64])
         }
     }
diff --git a/crates/render/src/fx_host.rs b/crates/render/src/fx_host.rs
index a0c3e7490..65bafe002 100644
--- a/crates/render/src/fx_host.rs
+++ b/crates/render/src/fx_host.rs
@@ -72,6 +72,14 @@ impl EffectHost for FxHost<'_, '_, '_> {
             return None;
         }
         let sub = self.r.nested();
+        // A 3D model or primitive layer has no 2D source of its own: an effect referencing one
+        // reads it as After Effects does — the layer rendered on its own through the comp's
+        // camera (Create 3D Layer Instance's effect), in the layer's effect space (the
+        // comp, centred on the layer's anchor).
+        if other.source.is_model() {
+            let buf = sub.solo_3d(self.ctx, other);
+            return Some(self.pixels(other, buf, false));
+        }
         // The cached layer buffer is shared; effects get their own copy.
         let buf = if masks_and_effects { (*sub.content_buf(self.ctx, other)?).clone() } else { sub.source(self.ctx, other)? };
         Some(self.pixels(other, buf, true))
@@ -90,12 +98,13 @@ impl EffectHost for FxHost<'_, '_, '_> {
     fn audio(&self, id: u64, start: f64, frames: usize, rate: u32) -> Option<Vec<f32>> {
         let other = self.ctx.layer(effectcraft_project::LayerId(id))?;
         let LayerSource::Footage { item } = &other.source else { return None };
-        let ItemKind::Footage(f) = &self.r.project.item(*item)?.kind else { return None };
+        let item = self.ctx.media_item(other, *item);
+        let ItemKind::Footage(f) = &self.r.project.item(item)?.kind else { return None };
         if !f.has_audio {
             return None;
         }
         let st = other.layer_time(Tick::from_seconds_f64(start));
-        self.r.footage.audio(*item, f, st, frames, rate)
+        self.r.footage.audio(item, f, st, frames, rate)
     }
 
     fn self_at(&self, layer_time: f64, effects: usize) -> Option<Buf> {
diff --git a/crates/render/src/layers.rs b/crates/render/src/layers.rs
index cac2add43..ce0a2dcde 100644
--- a/crates/render/src/layers.rs
+++ b/crates/render/src/layers.rs
@@ -2,7 +2,7 @@ use super::frames::adaptive_samples;
 use super::opts::{LayerTiming, Through};
 use super::{
     Arc, BlendMode, Buf, Comp, EvalCtx, Image, IndexedParallelIterator, IntoParallelRefIterator, IntoParallelRefMutIterator, Layer, LayerSource, Mat3,
-    MatteKind, ParallelIterator, Quality, Region, Renderer, Sampling, Tick, WarpOpts, cache, color, composite_warp_changed, masks, source_size, styles, vec2,
+    MatteKind, ParallelIterator, Quality, Region, Renderer, Sampling, Tick, WarpOpts, cache, color, composite_warp_changed, masks, styles, vec2,
 };
 
 /// Blend policy for placing a layer, including optional output-depth quantization.
@@ -52,7 +52,7 @@ impl<'a> Renderer<'a> {
             }
         }
         let t0 = web_time::Instant::now();
-        let size = source_size(self.project, layer);
+        let size = ctx.source_size(layer);
         let layer_size = if size.0 == 0 { [ctx.comp.width as f64, ctx.comp.height as f64] } else { [size.0 as f64, size.1 as f64] };
         let st = styles::render(ctx, layer, &content, layer_size);
         if let Some(t) = timing {
diff --git a/crates/render/src/lib.rs b/crates/render/src/lib.rs
index 0552a44d4..0c2f11e4c 100644
--- a/crates/render/src/lib.rs
+++ b/crates/render/src/lib.rs
@@ -60,6 +60,7 @@ pub use layers::{Placement, StyledLayer};
 pub(crate) use opts::Collapse3d;
 pub use opts::{LayerTiming, RenderOpts};
 use opts::{MAX_THROUGH, Through};
+pub use pipeline::{Collapsed, MediaOverride, PropertyOverride};
 
 pub struct Renderer<'a> {
     pub project: &'a Project,
diff --git a/crates/render/src/pipeline.rs b/crates/render/src/pipeline.rs
index 71ad426ce..d51344923 100644
--- a/crates/render/src/pipeline.rs
+++ b/crates/render/src/pipeline.rs
@@ -7,6 +7,8 @@ use super::{
     Arc, AutoKey, AutoPick, BlendMode, Buf, Comp, EffectCtx, EffectEnv, EvalCtx, Footage, FootageKind, FrameBlend, FrameRate, GroupKind, Image, ItemId,
     ItemKind, Layer, LayerCache, LayerSource, Params, Project, Quality, Region, Renderer, Tick, cache, color, masks, shapes, styles, text, three_d, vec2,
 };
+use effectcraft_keyframe::Value;
+use effectcraft_project::LayerId;
 
 /// Coordinate space and stack range shared by CPU and accelerated effect evaluation.
 #[derive(Clone, Copy)]
@@ -16,6 +18,88 @@ pub(crate) struct EffectStack {
     pub origin: [f64; 2],
 }
 
+/// A property value an Essential Properties override gives a layer of a collapsed precomp.
+#[derive(Clone, Debug)]
+pub struct PropertyOverride {
+    pub(crate) layer: LayerId,
+    pub(crate) prop: u64,
+    pub(crate) value: Value,
+    /// A Font control changes only the font of the target text, not its text.
+    pub(crate) font: bool,
+}
+
+/// A Media Replacement an Essential Properties override gives a footage layer of a collapsed
+/// precomp.
+#[derive(Clone, Copy, Debug)]
+pub struct MediaOverride {
+    pub(crate) layer: LayerId,
+    pub(crate) item: ItemId,
+}
+
+impl MediaOverride {
+    /// A Media Replacement of `layer`'s footage by `item`.
+    pub fn new(layer: LayerId, item: ItemId) -> Self {
+        MediaOverride { layer, item }
+    }
+}
+
+/// A collapsed precomp layer: the nested comp and the instance overrides that apply to it.
+pub struct Collapsed {
+    pub item: ItemId,
+    pub(crate) property_overrides: Vec<PropertyOverride>,
+    pub(crate) media_overrides: Vec<MediaOverride>,
+}
+
+/// The property and media overrides of a collapsed precomp layer. `None` when its Essential
+/// Properties group or the source comp's definitions are missing (the flattened path then
+/// preserves the old behaviour).
+fn collapsed_instance(ctx: &EvalCtx, layer: &Layer, item: ItemId) -> Option<(Vec<PropertyOverride>, Vec<MediaOverride>)> {
+    use effectcraft_project::essential::{self, ControlType, EgKind};
+    let over = essential::overridden(layer);
+    if over.is_empty() {
+        return Some((vec![], vec![]));
+    }
+    let g = essential::group(layer)?;
+    let eg = ctx.project.comp(item)?.essential.as_ref()?;
+    let mut property = vec![];
+    let mut fonts: Vec<PropertyOverride> = vec![];
+    let mut media = vec![];
+    g.walk("", &mut |_, p| {
+        if !over.contains(&p.uid) {
+            return;
+        }
+        let Some(control) = essential::control_of(&p.match_id) else { return };
+        let Some(ctl) = eg.resolve(control) else { return };
+        let value = ctx.value(layer, p);
+        match &ctl.kind {
+            EgKind::Property { .. } => {
+                let font = ctl.as_type == Some(ControlType::Font);
+                for (layer, prop) in ctl.kind.targets() {
+                    let o = PropertyOverride { layer, prop, value: value.clone(), font };
+                    if font { fonts.push(o) } else { property.push(o) }
+                }
+            }
+            EgKind::Media { layer: target } => {
+                let Value::Scalar(id) = value else { return };
+                let item = ItemId(id.max(0.0) as u64);
+                if matches!(ctx.project.item(item).map(|i| &i.kind), Some(ItemKind::Footage(_))) {
+                    media.push(MediaOverride { layer: *target, item });
+                }
+            }
+            _ => {}
+        }
+    });
+    // A Font control merges into the text its instance shows, after a whole-value (Text) override
+    // of the same property, as `essential::with_overrides` does: keep one entry per property.
+    for f in fonts {
+        match property.iter_mut().rev().find(|o| o.layer == f.layer && o.prop == f.prop) {
+            Some(o) => effectcraft_project::essential::merge_font(&mut o.value, &f.value),
+            None => property.push(f),
+        }
+    }
+    Some((property, media))
+}
+
 impl<'a> Renderer<'a> {
     pub fn new(project: &'a Project, footage: &'a dyn FootageSource, opts: RenderOpts) -> Renderer<'a> {
         Renderer {
@@ -122,8 +206,10 @@ impl<'a> Renderer<'a> {
 
     /// The nested comp of a precomp layer whose transformations collapse into this comp: the
     /// Collapse Transformations switch is on and the layer has no masks, effects or layer
-    /// styles (those force a flattened render of the precomp, as in After Effects).
-    pub fn collapsed(&self, ctx: &EvalCtx, layer: &Layer) -> Option<ItemId> {
+    /// styles (those force a flattened render of the precomp, as in After Effects). Essential
+    /// Properties overrides travel with it and are applied as the nested layers are evaluated,
+    /// so the nested comp is not rasterised at its frame.
+    pub fn collapsed(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Collapsed> {
         if !layer.switches.collapse || layer.switches.adjustment || self.depth > 12 {
             return None;
         }
@@ -140,24 +226,37 @@ impl<'a> Renderer<'a> {
         if styles::active(ctx, layer) {
             return None;
         }
-        // Instance overrides (Essential Properties) need the nested comp rendered on its own.
-        if !effectcraft_project::essential::overridden(layer).is_empty() {
+        // A composition proxy or frame blending is drawn by the flattened path (`precomp_source`);
+        // collapsing renders the nested comp directly and would ignore both.
+        if self.proxy_for(*item).is_some() || frame_blend_mode(ctx, layer) != FrameBlend::Off {
             return None;
         }
-        Some(*item)
+        let (property_overrides, media_overrides) = collapsed_instance(ctx, layer, *item)?;
+        Some(Collapsed { item: *item, property_overrides, media_overrides })
     }
 
     /// A renderer and context that draw a collapsed precomp's layers straight into this comp:
     /// their transforms are concatenated with the precomp layer's (one resample, no
     /// rasterisation at the precomp's bounds), their opacity multiplied by `opacity`, and their
     /// 3D layers use this comp's camera and lights.
-    pub fn collapse_into(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, item: ItemId, opacity: f32) -> Option<(Renderer<'a>, EvalCtx<'a>)> {
+    pub fn collapse_into<'p>(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &'p Collapsed, opacity: f32) -> Option<(Renderer<'p>, EvalCtx<'p>)>
+    where
+        'a: 'p,
+    {
+        let item = collapsed.item;
         let nc = self.project.comp(item)?;
         let t = ctx.nested_time(layer);
         if !nc.covers(t) {
             return None;
         }
-        let nctx = EvalCtx { comp_id: item, comp: nc, time: t, ..*ctx };
+        let nctx = EvalCtx {
+            comp_id: item,
+            comp: nc,
+            time: t,
+            property_overrides: &collapsed.property_overrides,
+            media_overrides: &collapsed.media_overrides,
+            ..*ctx
+        };
         let (l2c, _) = ctx.layer_to_comp(layer);
         let outer = Some(self.outer.map_or(l2c, |o| o * l2c));
         let world = ctx.world_matrix(layer);
@@ -189,19 +288,19 @@ impl<'a> Renderer<'a> {
     /// that then takes the precomp layer's track matte, Preserve Transparency and blend mode.
     /// Returns the region left to re-quantise (nested layers drawn straight into `canvas`
     /// quantise their own footprints).
-    pub(crate) fn draw_collapsed(&self, ctx: &EvalCtx<'a>, layer: &Layer, item: ItemId, canvas: &mut Image, blank: bool) -> Region {
+    pub(crate) fn draw_collapsed(&self, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &Collapsed, canvas: &mut Image, blank: bool) -> Region {
         let opacity = ctx.opacity(layer) as f32 * self.opacity_mul;
         if opacity <= 0.0 {
             return Region::Empty;
         }
         let matte = layer.track_matte.is_some_and(|tm| tm.layer != layer.id && ctx.comp.layer(tm.layer).is_some());
         if layer.blend_mode == BlendMode::Normal && !matte && !layer.preserve_transparency {
-            if let Some((sub, nctx)) = self.collapse_into(ctx, layer, item, opacity) {
+            if let Some((sub, nctx)) = self.collapse_into(ctx, layer, collapsed, opacity) {
                 sub.draw_comp(&nctx, canvas, blank);
             }
             return Region::Empty;
         }
-        let Some((sub, nctx)) = self.collapse_into(ctx, layer, item, 1.0) else { return Region::Empty };
+        let Some((sub, nctx)) = self.collapse_into(ctx, layer, collapsed, 1.0) else { return Region::Empty };
         let mut iso = Image::new(canvas.width, canvas.height);
         sub.draw_comp(&nctx, &mut iso, true);
         self.composite_iso(ctx, layer, iso, canvas, opacity);
@@ -230,6 +329,7 @@ impl<'a> Renderer<'a> {
         let continuous = match layer.source {
             LayerSource::Text | LayerSource::Shape => true,
             LayerSource::Footage { item } => {
+                let item = ctx.media_item(layer, item);
                 layer.switches.collapse && matches!(self.project.item(item).map(|i| &i.kind), Some(ItemKind::Footage(f)) if is_vector_footage(f))
             }
             _ => false,
@@ -267,7 +367,7 @@ impl<'a> Renderer<'a> {
     }
 
     pub(crate) fn ctx(&self, comp_id: ItemId, comp: &'a Comp, t: Tick) -> EvalCtx<'a> {
-        EvalCtx { project: self.project, comp_id, comp, time: t, expr: self.expr, footage: Some(self.footage) }
+        EvalCtx { project: self.project, comp_id, comp, time: t, expr: self.expr, footage: Some(self.footage), property_overrides: &[], media_overrides: &[] }
     }
 
     /// This renderer with another accelerator (or none): the passes of
@@ -406,7 +506,7 @@ impl<'a> Renderer<'a> {
                 blank = false;
             } else {
                 let changed = match self.collapsed(ctx, visible[i]) {
-                    Some(item) => self.draw_collapsed(ctx, visible[i], item, canvas, blank),
+                    Some(collapsed) => self.draw_collapsed(ctx, visible[i], &collapsed, canvas, blank),
                     None => self.draw_layer(ctx, visible[i], canvas, blank),
                 };
                 i += 1;
@@ -637,7 +737,8 @@ impl<'a> Renderer<'a> {
                 Some(Buf { img: sub.comp_frame(*item, lt), offset: [0.0; 2], scale: bs })
             }
             LayerSource::Footage { item } => {
-                let it = self.project.item(*item)?;
+                let item = ctx.media_item(layer, *item);
+                let it = self.project.item(item)?;
                 let ItemKind::Footage(f) = &it.kind else { return None };
                 if !f.has_video {
                     return None;
@@ -645,7 +746,7 @@ impl<'a> Renderer<'a> {
                 // Continuously rasterised vector footage: drawn at the on-screen scale.
                 if layer.switches.collapse && is_vector_footage(f) {
                     let k = self.raster_scale(ctx, layer);
-                    if let Some(img) = self.footage.vector_frame(*item, f, k) {
+                    if let Some(img) = self.footage.vector_frame(item, f, k) {
                         let mut buf = Buf { img: (*img).clone(), offset: [0.0; 2], scale: k };
                         if let Some(c) = self.pipe.media_in(f) {
                             color::convert(&mut buf.img, &c);
@@ -655,10 +756,10 @@ impl<'a> Renderer<'a> {
                 }
                 let lt = ctx.source_time(layer);
                 // The proxy is decoded instead, at its own size, and fills the footage's frame.
-                let proxy = self.proxy_for(*item);
+                let proxy = self.proxy_for(item);
                 let pf = proxy.unwrap_or(f);
                 let size = self.reduced_size(f.width, f.height).filter(|_| proxy.is_none());
-                let img = self.footage_frame(ctx, layer, *item, pf, lt, size)?;
+                let img = self.footage_frame(ctx, layer, item, pf, lt, size)?;
                 Some(self.footage_buf(&img, pf, f.width, f.height))
             }
             LayerSource::Text => Some(self.authored(text::render(ctx, layer, self.raster_scale(ctx, layer)))),
@@ -836,6 +937,30 @@ impl<'a> Renderer<'a> {
         self.source(ctx, layer)
     }
 
+    /// A 3D model or primitive layer rendered on its own, through the comp's camera: what an
+    /// effect layer parameter reads when it references one, as After Effects, which renders 3D
+    /// layers through the active camera. The comp's pixels at this render's scale; the layer's
+    /// blend mode, track matte and video switch don't apply (a source read, not a composite —
+    /// the solo clone of a 3D track matte, see `three_d::adv`).
+    pub(crate) fn solo_3d(&self, ctx: &EvalCtx, layer: &Layer) -> Buf {
+        let s = self.opts.scale;
+        let w = ((ctx.comp.width as f64 * s).ceil() as u32).max(1);
+        let h = ((ctx.comp.height as f64 * s).ceil() as u32).max(1);
+        let mut canvas = Image::new(w, h);
+        // Outside the layer's in/out points there is nothing to read: the copy is transparent
+        // there, like any other layer reference (the 3D pipelines don't gate on the range).
+        if !layer.is_active_at(ctx.time) {
+            return Buf { img: canvas, offset: [0.0; 2], scale: s };
+        }
+        let mut solo = layer.clone();
+        solo.track_matte = None;
+        solo.blend_mode = effectcraft_color::BlendMode::Normal;
+        solo.preserve_transparency = false;
+        solo.switches.video = true;
+        three_d::compose::draw_run(self, ctx, &[&solo], &mut canvas);
+        Buf { img: canvas, offset: [0.0; 2], scale: s }
+    }
+
     /// Layer pixels after source → masks → effects (no layer styles).
     pub fn content_buf(&self, ctx: &EvalCtx, layer: &Layer) -> Option<Arc<Buf>> {
         self.content_buf_timed(ctx, layer, None).map(|(b, _)| b)
diff --git a/crates/render/src/tests.rs b/crates/render/src/tests.rs
index f04bd4be2..38baa8f3e 100644
--- a/crates/render/src/tests.rs
+++ b/crates/render/src/tests.rs
@@ -1276,3 +1276,194 @@ fn workers_rendering_a_layer_at_once_share_one_buffer() {
     assert!(bufs.iter().all(|b| std::sync::Arc::ptr_eq(b, &bufs[0])), "one shared buffer");
     assert_eq!(cache.stats().entries, 1);
 }
+
+// ------------------------------------------------------------------------------ 3D layer instances
+
+/// A red triangle in the Z = 0 plane (the engine instance3d tests' glTF, buffer embedded as a
+/// data URI), parsed in memory: a FootageSource that knows one model item.
+const TRIANGLE: &str = r#"{
+  "asset": {"version": "2.0"},
+  "scenes": [{"nodes": [0]}],
+  "nodes": [{"mesh": 0}],
+  "meshes": [{"primitives": [{"attributes": {"POSITION": 0, "NORMAL": 1}, "material": 0}]}],
+  "materials": [{"pbrMetallicRoughness": {"baseColorFactor": [1.0, 0.0, 0.0, 1.0]}}],
+  "buffers": [{"byteLength": 72, "uri": "data:application/octet-stream;base64,AACAvwAAgL8AAAAAAACAPwAAgL8AAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/"}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 36},
+    {"buffer": 0, "byteOffset": 36, "byteLength": 36}
+  ],
+  "accessors": [
+    {"bufferView": 0, "componentType": 5126, "type": "VEC3", "count": 3, "min": [-1.0, -1.0, 0.0], "max": [1.0, 1.0, 0.0]},
+    {"bufferView": 1, "componentType": 5126, "type": "VEC3", "count": 3}
+  ]
+}"#;
+
+struct SoloModels;
+
+impl crate::FootageSource for SoloModels {
+    fn frame(&self, _: ItemId, _: &effectcraft_project::Footage, _: Tick) -> Option<std::sync::Arc<crate::Image>> {
+        None
+    }
+    fn model(&self, _: ItemId, f: &effectcraft_project::Footage) -> Option<std::sync::Arc<effectcraft_model::Model>> {
+        effectcraft_model::load(&f.path, TRIANGLE.as_bytes(), &|_| None).ok().map(std::sync::Arc::new)
+    }
+}
+
+/// A red triangle 3D model, a camera panned right by `pan` px and, on top of the stack, the
+/// copy: a solid with a 3D Layer Instance effect referencing the model.
+fn instance_scene(pan: f64) -> (Project, ItemId) {
+    let (mut p, cid, comp) = setup();
+    // Models are Advanced 3D (layer.newModel switches a Classic comp over).
+    p.comp_mut(cid).unwrap().renderer = effectcraft_project::Renderer::Advanced3D;
+    let mid = p.add_item(
+        "Triangle",
+        Label::Red,
+        None,
+        ItemKind::Footage(effectcraft_project::Footage {
+            path: "Triangle.gltf".into(),
+            kind: effectcraft_project::FootageKind::Model,
+            frame_rate: FrameRate::FPS_30,
+            codec: "glTF".into(),
+            ..Default::default()
+        }),
+    );
+    let model = build::layer(&mut p, &comp, "Triangle", LayerSource::Model { item: mid }, (200, 100), None);
+    let mut cam = build::layer(&mut p, &comp, "Camera", LayerSource::Camera, (200, 100), None);
+    for path in ["transform/position", "transform/poi"] {
+        let pr = cam.props.prop_mut(path).unwrap();
+        let Value::Vec3(v) = pr.value else { panic!("{path}: {:?}", pr.value) };
+        pr.value = Value::Vec3([v[0] + pan, v[1], v[2]]);
+    }
+    let mut owner = solid(&mut p, &comp, [1.0, 1.0, 1.0], 200, 100);
+    add_effect_200(&mut p, &mut owner, "ec.3d.instance3d", &[("layer", Value::Layer(Some(model.id.0)))]);
+    p.comp_mut(cid).unwrap().layers = vec![cam, owner, model];
+    (p, cid)
+}
+
+fn render_models(p: &Project, cid: ItemId, t: Tick, cache: Option<&crate::LayerCache>) -> crate::Image {
+    let mut r = crate::Renderer::new(p, &SoloModels, crate::RenderOpts::default());
+    r.cache = cache;
+    r.comp_frame(cid, t)
+}
+
+/// The coverage-weighted centre of the triangle (x): where its drawn pixels are, lit or not.
+fn cover_x(img: &crate::Image) -> f32 {
+    let (mut m, mut sx) = (0.0, 0.0);
+    for y in 0..img.height {
+        for x in 0..img.width {
+            let a = img.get(x as i64, y as i64)[3];
+            m += a;
+            sx += a * x as f32;
+        }
+    }
+    assert!(m > 1.0, "the triangle is drawn");
+    sx / m
+}
+
+/// Create 3D Layer Instance: the copy (the owner) is cached, and its key covers what the
+/// referenced model's solo render depends on — the camera, and the model's in/out gate.
+#[test]
+fn an_instance_of_a_model_is_cached_and_follows_the_camera() {
+    let t = Tick::from_seconds_f64(1.0);
+    let (p, cid) = instance_scene(0.0);
+    let (q, _) = instance_scene(40.0);
+    let key_at = |p: &Project, t: Tick| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    assert_ne!(key_at(&p, t), key_at(&q, t), "moving the camera changes the copy's key");
+    // The same layer at a later time, outside its in/out range: the read turns transparent.
+    let mut out = p.clone();
+    out.comp_mut(cid).unwrap().layers[2].out_point = Tick::from_seconds_f64(0.5);
+    assert_ne!(key_at(&out, Tick::from_seconds_f64(0.25)), key_at(&out, t), "leaving the model's in/out range changes the copy's key");
+    // Two renders of one time: the second is served from the cache.
+    let cache = crate::LayerCache::default();
+    let here = render_models(&p, cid, t, Some(&cache));
+    let again = render_models(&p, cid, t, Some(&cache));
+    assert_same(&again, &render_models(&p, cid, t, None), "the second render is the cached one");
+    assert!(cache.stats().hits > 0, "the copy was served from the cache");
+    // Panning the camera: the copy (and the model) move with it.
+    let panned = render_models(&q, cid, t, Some(&cache));
+    assert_same(&panned, &render_models(&q, cid, t, None), "cached render after the camera moved");
+    let (a, b) = (cover_x(&here), cover_x(&panned));
+    assert!(b < a - 20.0, "panning the camera right moves the copy left: {a} -> {b}");
+}
+
+/// The camera's depth of field blurs the solo render (focus, aperture, iris, highlights) —
+/// none of it is in the projection matrix: changing any of it must change the copy's key, or
+/// it would serve the un-blurred pixels.
+#[test]
+fn the_copy_key_covers_the_cameras_depth_of_field() {
+    let t = Tick::from_seconds_f64(1.0);
+    let (p, cid) = instance_scene(0.0);
+    let set_dof = |p: &Project, on: bool, focus: f64, aperture: f64| {
+        let mut q = p.clone();
+        let cam = &mut q.comp_mut(cid).unwrap().layers[0];
+        for (path, v) in
+            [("cameraOptions/dof", Value::Bool(on)), ("cameraOptions/focusDistance", Value::Scalar(focus)), ("cameraOptions/aperture", Value::Scalar(aperture))]
+        {
+            cam.props.prop_mut(path).unwrap().value = v;
+        }
+        q
+    };
+    let key_at = |p: &Project| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    let ka = key_at(&set_dof(&p, true, 500.0, 20.0));
+    let kb = key_at(&set_dof(&p, true, 500.0, 40.0)); // aperture
+    let kc = key_at(&set_dof(&p, true, 700.0, 20.0)); // focus
+    let kd = key_at(&set_dof(&p, false, 500.0, 20.0)); // the switch off
+    assert!(ka != kb && ka != kc && ka != kd && kb != kc, "aperture, focus and the switch each change the key");
+}
+
+/// A model with an animation clip selected is posed at its layer time: every time is its own
+/// entry. Without one (the default) the pose is the same at every time: one key inside the
+/// in/out range, as before.
+#[test]
+fn the_copy_key_covers_an_animated_models_layer_time() {
+    let (p, cid) = instance_scene(0.0);
+    let (t0, t1) = (Tick::from_seconds_f64(0.5), Tick::from_seconds_f64(1.0));
+    let key_at = |p: &Project, t: Tick| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[1], 1.0, false, false).unwrap()
+    };
+    assert_eq!(key_at(&p, t0), key_at(&p, t1), "a model without a clip keeps one key across times");
+    let mut q = p.clone();
+    q.comp_mut(cid).unwrap().layers[2].props.prop_mut("geometryOptions/animation").unwrap().value = Value::Enum(1);
+    assert_ne!(key_at(&q, t0), key_at(&q, t1), "an animated model's key follows its layer time");
+    // Two times and back: each is rendered fresh, none served another time's pixels.
+    let cache = crate::LayerCache::default();
+    let first = render_models(&q, cid, t0, Some(&cache));
+    let second = render_models(&q, cid, t1, Some(&cache));
+    assert_eq!(cache.stats().hits, 0, "the second time is not served the first time's pixels");
+    assert_same(&second, &render_models(&q, cid, t1, None), "the second time is a fresh render");
+    let again = render_models(&q, cid, t0, Some(&cache));
+    assert_eq!(cache.stats().hits, 1, "the first time is served on the way back");
+    assert_same(&again, &first, "the way back is the first time's pixels");
+}
+
+/// An Environment light's image lights Advanced 3D models — its source can be any layer's
+/// render: with one on, the read is not cached, so changes to it cannot reuse stale pixels.
+#[test]
+fn an_environment_light_makes_the_copy_uncached() {
+    let (p, cid) = instance_scene(0.0);
+    let mut q = p.clone();
+    let comp = q.comp(cid).unwrap().clone();
+    let env = build::layer(&mut q, &comp, "Env", LayerSource::Light { kind: effectcraft_project::LightKind::Environment }, (200, 100), None);
+    q.comp_mut(cid).unwrap().layers.insert(0, env);
+    let t = Tick::from_seconds_f64(1.0);
+    let key_at = |p: &Project| {
+        let c = p.comp(cid).unwrap();
+        crate::cache::layer_key(&crate::EvalCtx::new(p, cid, c, t), &c.layers[2], 1.0, false, false)
+    };
+    assert!(key_at(&q).is_none(), "with an Environment light the read is not cached");
+    let cache = crate::LayerCache::default();
+    let a = render_models(&q, cid, t, Some(&cache));
+    let b = render_models(&q, cid, t, Some(&cache));
+    assert_same(&a, &b, "two fresh renders agree");
+    assert_eq!(cache.stats().hits, 0, "nothing is served from the cache");
+    // The light off (not lighting): the cache comes back.
+    q.comp_mut(cid).unwrap().layers[0].switches.video = false;
+    assert!(key_at(&q).is_some(), "the light off, the read is cached again");
+}
diff --git a/crates/render/src/tests/audio_fx.rs b/crates/render/src/tests/audio_fx.rs
index aced8208e..242a5a5e2 100644
--- a/crates/render/src/tests/audio_fx.rs
+++ b/crates/render/src/tests/audio_fx.rs
@@ -2,7 +2,7 @@
 
 use std::sync::Arc;
 
-use effectcraft_keyframe::Value;
+use effectcraft_keyframe::{Keyframe, Value};
 use effectcraft_project::build::{self, Ids};
 use effectcraft_project::{Comp, Footage, FootageKind, ItemId, ItemKind, LayerSource, Project, Solid};
 use effectcraft_time::{FrameRate, Tick};
@@ -148,6 +148,42 @@ fn stereo_mixer_pans() {
     assert!(m.chunks(2).all(|f| f[0].abs() < 1e-6 && (f[1] - 0.5).abs() < 1e-6), "{:?}", &m[..4]);
 }
 
+/// Key `prop` of layer 0 (`effect`: in its first effect, else in Audio) from `a` at 0 s to `b` at 1 s.
+fn key(p: &mut Project, cid: ItemId, effect: bool, prop: &str, a: Value, b: Value) {
+    let l = &mut p.comp_mut(cid).unwrap().layers[0];
+    let g = if effect { l.props.sub_mut("effects").unwrap().children[0].as_group_mut().unwrap() } else { l.props.sub_mut("audio").unwrap() };
+    g.get_mut(prop).unwrap().keys = vec![Keyframe::new(Tick::ZERO, a), Keyframe::new(Tick::from_seconds_f64(1.0), b)];
+}
+
+/// Left samples of a mix of constant 0.5 audio over the layer's 1 s, in blocks of `block` samples.
+fn left_ramp(p: &Project, cid: ItemId, block: usize) -> Vec<f32> {
+    fn half(_: f64) -> (f32, f32) {
+        (0.5, 0.5)
+    }
+    let mut m = vec![];
+    for k in 0..SR as usize / block {
+        m.extend(mix(p, &Signal(half), cid, (k * block) as f64 / SR as f64, block));
+    }
+    m.iter().step_by(2).copied().collect()
+}
+
+/// Keyframed Audio Levels and Stereo Mixer levels ramp smoothly inside a block (export mixes one
+/// second at a time), instead of holding the value at the block's first sample.
+#[test]
+fn animated_levels_ramp_within_a_block() {
+    let (mut levels, lc) = comp_with(None, &[], false);
+    key(&mut levels, lc, false, "levels", Value::Vec2([-60.0, -60.0]), Value::Vec2([0.0, 0.0]));
+    let (mut mixer, mc) = comp_with(Some("ec.audio.stereomixer"), &[], false);
+    key(&mut mixer, mc, true, "leftLevel", Value::Scalar(0.0), Value::Scalar(100.0));
+    for (name, p, cid, mid) in [("levels", &levels, lc, 0.5 * 10f32.powf(-1.5)), ("stereo mixer", &mixer, mc, 0.25)] {
+        let one = left_ramp(p, cid, SR as usize);
+        assert!(one.windows(2).all(|w| w[1] >= w[0]), "{name}: not monotonic");
+        assert!(one[100] < one[4000] && one[4000] < one[7900], "{name}: {} {} {}", one[100], one[4000], one[7900]);
+        assert!((one[4000] / mid - 1.0).abs() < 0.05, "{name}: {} at 0.5 s, want {mid}", one[4000]);
+        assert_eq!(one, left_ramp(p, cid, 320), "{name}: block size changes the result");
+    }
+}
+
 #[test]
 fn tone_makes_a_solid_audible_at_its_frequency() {
     let mut vals: Vec<(&str, Value)> = vec![("frequency1", Value::Scalar(500.0))];
diff --git a/crates/render/src/tests/collapse.rs b/crates/render/src/tests/collapse.rs
index 797960033..eb340a4ca 100644
--- a/crates/render/src/tests/collapse.rs
+++ b/crates/render/src/tests/collapse.rs
@@ -3,7 +3,7 @@
 use effectcraft_color::{BlendMode, Label};
 use effectcraft_keyframe::{TextDoc, Value};
 use effectcraft_project::build::{self, Ids};
-use effectcraft_project::{BitDepth, Comp, ItemId, ItemKind, Layer, LayerSource, Project, Quality, Solid};
+use effectcraft_project::{BitDepth, Comp, FrameBlend, ItemId, ItemKind, Layer, LayerSource, Project, Quality, Solid};
 use effectcraft_time::{FrameRate, Tick};
 
 use crate::{EvalCtx, Image, NoFootage, RenderOpts, Renderer, render_frame};
@@ -110,6 +110,66 @@ fn masks_on_a_collapsed_layer_force_a_flattened_render() {
     assert!(max_diff(&a, &b) < 1e-4, "{}", max_diff(&a, &b));
 }
 
+/// #1747: the flattened path honours a composition proxy and frame blending; a collapsed layer
+/// renders the nested comp directly and ignores both, so such a layer must not collapse.
+#[test]
+fn proxy_and_frame_blending_keep_a_precomp_on_the_flattened_path() {
+    let (mut p, cid) = scene(true, false);
+    let id = p.comp(cid).unwrap().layers[0].id;
+    let collapses = |p: &Project| {
+        let r = Renderer::new(p, &NoFootage, RenderOpts::default());
+        let ctx = EvalCtx::new(p, cid, p.comp(cid).unwrap(), Tick::ZERO);
+        r.collapsed(&ctx, ctx.comp.layer(id).unwrap()).is_some()
+    };
+    assert!(collapses(&p), "a plain precomp collapses");
+    // Frame blending needs both the comp's switch and the layer's.
+    p.comp_mut(cid).unwrap().enable_frame_blending = true;
+    p.comp_mut(cid).unwrap().layers[0].switches.frame_blend = FrameBlend::FrameMix;
+    assert!(!collapses(&p), "frame blending keeps the flattened path");
+    p.comp_mut(cid).unwrap().enable_frame_blending = false;
+    p.comp_mut(cid).unwrap().layers[0].switches.frame_blend = FrameBlend::Off;
+    // A composition proxy stands in for the precomp's pixels.
+    let LayerSource::Comp { item } = p.comp(cid).unwrap().layers[0].source else { panic!("a precomp layer") };
+    let proxy =
+        effectcraft_project::Proxy { footage: effectcraft_project::Footage { has_video: true, width: 32, height: 32, ..Default::default() }, enabled: true };
+    p.item_mut(item).unwrap().proxy = Some(Box::new(proxy));
+    assert!(!collapses(&p), "a proxy keeps the flattened path");
+}
+
+/// #1747: an effect on B that reads A must not reuse its cached buffer when two collapsed
+/// instances give A different static overrides (`hash_values` only sees animated values).
+#[test]
+fn referenced_layer_overrides_change_the_owner_cache_key() {
+    let mut p = project();
+    let comp = Comp::new(100, 100, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let a = solid(&mut p, &comp, [1.0, 1.0, 1.0], (40, 40), [30.0, 50.0, 0.0]);
+    let aid = a.id;
+    let mut b = solid(&mut p, &comp, [1.0, 1.0, 1.0], (100, 100), [50.0, 50.0, 0.0]);
+    let bid = b.id;
+    let mut next = p.next_id;
+    let mut ids = Ids(&mut next);
+    let spec = effectcraft_effects::find("ec.channel.setmatte").unwrap();
+    let mut fx = effectcraft_effects::instantiate(spec, &mut ids, spec.name, [100.0, 100.0]);
+    fx.prop_mut("takeMatteFromLayer").unwrap().value = Value::Layer(Some(a.id.0));
+    p.next_id = next;
+    b.props.sub_mut("effects").unwrap().children.push(fx.into());
+    let mut c = comp;
+    c.layers = vec![b, a];
+    let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(c.into()));
+    let comp = p.comp(cid).unwrap();
+    let b = comp.layer(bid).unwrap();
+    let opacity = comp.layer(aid).unwrap().props.prop("transform/opacity").unwrap().uid;
+    let key = |value: f64| {
+        let overrides = [crate::PropertyOverride { layer: aid, prop: opacity, value: Value::Scalar(value), font: false }];
+        let ctx =
+            EvalCtx { project: &p, comp_id: cid, comp, time: Tick::ZERO, expr: None, footage: None, property_overrides: &overrides, media_overrides: &[] };
+        crate::cache::layer_key(&ctx, b, 1.0, false, false)
+    };
+    let (opaque, half) = (key(100.0), key(50.0));
+    assert!(opaque.is_some(), "the owner is cacheable");
+    assert_ne!(opaque, half, "A's static override changes B's key");
+}
+
 #[test]
 fn collapsed_3d_layers_join_the_parent_scene() {
     // Parent: a red 3D solid at z = 0 above (in the stack) a collapsed 3D precomp holding a
diff --git a/crates/render/src/tests/time.rs b/crates/render/src/tests/time.rs
index 8739140de..e9599f70b 100644
--- a/crates/render/src/tests/time.rs
+++ b/crates/render/src/tests/time.rs
@@ -134,7 +134,16 @@ fn input_keys_ignore_later_effects() {
     }
     let key = |p: &Project| {
         let comp = p.comp(cid).unwrap();
-        let ctx = crate::EvalCtx { project: p, comp_id: cid, comp, time: Tick::from_seconds_f64(0.5), expr: None, footage: None };
+        let ctx = crate::EvalCtx {
+            project: p,
+            comp_id: cid,
+            comp,
+            time: Tick::from_seconds_f64(0.5),
+            expr: None,
+            footage: None,
+            property_overrides: &[],
+            media_overrides: &[],
+        };
         let l = &comp.layers[0];
         (crate::cache::input_key(&ctx, l, 1.0, false, false, 1), crate::cache::input_key(&ctx, l, 1.0, false, false, 2))
     };
diff --git a/crates/render/src/text.rs b/crates/render/src/text.rs
index 132da9bf6..19c17d53f 100644
--- a/crates/render/src/text.rs
+++ b/crates/render/src/text.rs
@@ -42,7 +42,8 @@ pub struct CharXf {
     pub stroke_hsb: [f64; 3],
     pub stroke_opacity: f64,
     pub stroke_width: f64,
-    /// Tracking (pixels) added before / after the character.
+    /// Tracking (pixels: an animator's Tracking Amount, as After Effects) added before / after
+    /// the character.
     pub track_before: f64,
     pub track_after: f64,
     /// Line Anchor (percent) and the selection weight it was set with.
@@ -509,6 +510,7 @@ pub struct PlacedGlyph {
     pub fill: [f32; 4],
     pub stroke: [f32; 4],
     pub stroke_width: f64,
+    pub join: effectcraft_path::Join,
     /// Faux Bold (or synthetic bold for a family without a bold face): how far the outline grows
     /// on every side, in character space (0 when not bold).
     pub bold: f64,
@@ -694,6 +696,9 @@ pub fn text_geom(ctx: &EvalCtx, layer: &Layer) -> Option<TextGeom> {
         let (mut la, mut la_k) = (50.0 * f64::from(align_index(justify)), 0.0);
         for gi in li_start..li_end {
             let x = &xfs[gi];
+            // An animator's Tracking Amount is in pixels, whatever the font size (After Effects
+            // 2026: Amount 30 adds 30 px between selected characters at 80 px and at 40 px), unlike
+            // the Character panel's tracking in 1/1000 em.
             pen += x.track_before;
             shift[gi] = pen;
             pen += x.track_after + vadv[gi];
@@ -804,9 +809,12 @@ pub fn text_geom(ctx: &EvalCtx, layer: &Layer) -> Option<TextGeom> {
         };
         // Outline relative to the pivot.
         let local = kurbo::Affine::translate((o[0] - pivot[0], o[1] - pivot[1])) * outline;
-        let char_m = Mat4::rotate_z(x.rotation)
+        // Rx · Ry · Rz (Z turns first): the order After Effects gives a 3D layer's X / Y / Z
+        // Rotation too. #1876 moves layers to it with a helper, `Mat4::rotation_xyz`; once both
+        // land, this should call that helper (one convention, one place).
+        let char_m = Mat4::rotate_x(x.rotation_x)
             * Mat4::rotate_y(x.rotation_y)
-            * Mat4::rotate_x(x.rotation_x)
+            * Mat4::rotate_z(x.rotation)
             * Mat4::from_mat3_affine(&Mat3::skew_deg(-x.skew, x.skew_axis))
             * Mat4::scale(Vec3::from(x.scale) / 100.0)
             * Mat4::translate(-Vec3::from(x.anchor));
@@ -831,6 +839,7 @@ pub fn text_geom(ctx: &EvalCtx, layer: &Layer) -> Option<TextGeom> {
             fill,
             stroke,
             stroke_width: (base_stroke_w + x.stroke_width).max(0.0),
+            join: path_join(doc.line_join),
             bold: if g.synth_bold { FAUX_BOLD_RADIUS * g.size } else { 0.0 },
             apply_fill: st.apply_fill,
             char_index: g.char_index,
@@ -846,6 +855,15 @@ pub fn glyph_paths(ctx: &EvalCtx, layer: &Layer) -> Vec<(BezPath, CharXf)> {
     text_geom(ctx, layer).map(|t| t.glyphs.iter().map(|g| (g.path(), g.xf)).collect()).unwrap_or_default()
 }
 
+fn path_join(j: effectcraft_keyframe::LineJoin) -> effectcraft_path::Join {
+    use effectcraft_keyframe::LineJoin;
+    match j {
+        LineJoin::Miter => effectcraft_path::Join::Miter,
+        LineJoin::Round => effectcraft_path::Join::Round,
+        LineJoin::Bevel => effectcraft_path::Join::Bevel,
+    }
+}
+
 /// One paint pass of a glyph: fill (false) or stroke (true).
 type Pass = (usize, bool);
 
@@ -912,7 +930,7 @@ fn raster_pass(g: &PlacedGlyph, stroke: bool, paths: &[BezPath], m: &Mat3, rect:
         }
         outer
     } else if stroke {
-        let st = StrokeStyle { width: g.stroke_width, join: effectcraft_path::Join::Round, ..Default::default() };
+        let st = StrokeStyle { width: g.stroke_width, join: g.join, ..Default::default() };
         effectcraft_path::stroke_coverage(paths, &st, &mm, w, h)
     } else {
         grown_coverage(paths, &mm, w, h, bold)
diff --git a/crates/render/src/text/tests.rs b/crates/render/src/text/tests.rs
index 43f53dce9..503ea097c 100644
--- a/crates/render/src/text/tests.rs
+++ b/crates/render/src/text/tests.rs
@@ -222,7 +222,7 @@ fn tracking_line_anchor_and_character_offset() {
     let w0 = bounds_of(&glyph_paths(&ctx(&p, cid, 0.0), &p.comp(cid).unwrap().layers[0]));
     set(&mut p.comp_mut(cid).unwrap().layers[0], "text/animators/#1/properties/tracking", Value::Scalar(20.0));
     let w1 = bounds_of(&glyph_paths(&ctx(&p, cid, 0.0), &p.comp(cid).unwrap().layers[0]));
-    // 4 chars with 20 px tracking: the last glyph moves ~ 3.5 × 20 px further (before & after).
+    // Tracking Amount 20 (pixels, as After Effects): the last glyph moves ~ 3.5 × 20 px further (before & after).
     assert!((w1.width() - w0.width() - 3.0 * 20.0).abs() < 1.5, "{} {}", w0.width(), w1.width());
     assert!((w1.x0 - w0.x0 - 10.0).abs() < 1.0, "first char shifts by half its tracking: {} {}", w0.x0, w1.x0);
     // Line Anchor 100%: tracking grows to the left.
@@ -262,7 +262,7 @@ fn tracking_grows_from_each_paragraphs_alignment() {
         p.comp_mut(cid).unwrap().layers.push(l);
         glyph_paths(&ctx(&p, cid, 0.0), &p.comp(cid).unwrap().layers[0])
     };
-    // 4 chars with 20 px of tracking each, half before and half after.
+    // Tracking Amount 20 (pixels): 20 px of tracking each, half before and half after.
     for (justify, x0, centre, x1) in [(Justify::Left, 10.0, 40.0, 70.0), (Justify::Center, -30.0, 0.0, 30.0), (Justify::Right, -70.0, -40.0, -10.0)] {
         let d = TextDoc { justify, ..doc("ABCD", 40.0) };
         let (w0, w1) = (bounds_of(&tracked(d.clone(), 0.0)), bounds_of(&tracked(d, 20.0)));
@@ -504,6 +504,37 @@ fn per_character_3d_projects_characters() {
     assert!(b[2] - b[0] < flat[2] - flat[0] && b[2] > b[0] + 10, "{b:?} {flat:?}");
 }
 
+/// After Effects 2026 (case 931: "H", 400 px, per-character 3D, X / Y / Z Rotation 40 / 30 /
+/// 20): a character turns like a 3D layer, Rx · Ry · Rz (Z first), so its matrix is the same
+/// product as a layer's X / Y / Z Rotation. The render then matches AE (3 of 5184 grid points
+/// off at edges; with Rz · Ry · Rx 23).
+#[test]
+fn per_character_rotation_turns_z_first_as_a_3d_layer() {
+    let (mut p, cid, comp) = setup(400, 300);
+    let mut l = text_layer(&mut p, &comp, doc("H", 80.0));
+    l.switches.three_d = true;
+    animator(&mut p, &mut l, &["rotation"], &["range"]);
+    let mut next = p.next_id;
+    let mut extra = build::text_anim_props(&mut Ids(&mut next), "rotation", true);
+    p.next_id = next;
+    let props: &mut PropGroup = l.props.group_mut("text/animators/#1/properties").unwrap();
+    props.children.retain(|c| c.match_id() != "rotation");
+    props.children.extend(extra.drain(..).map(Into::into));
+    for (id, v) in [("rotationX", 40.0), ("rotationY", 30.0), ("rotation", 20.0)] {
+        props.get_mut(id).unwrap().value = Value::Scalar(v);
+    }
+    l.props.sub_mut("text").unwrap().get_mut("perChar3d").unwrap().value = Value::Bool(true);
+    p.comp_mut(cid).unwrap().layers.push(l);
+    let geom = text_geom(&ctx(&p, cid, 0.0), &p.comp(cid).unwrap().layers[0]).unwrap();
+    let g = &geom.glyphs[0];
+    let want = Mat4::rotate_x(40.0) * Mat4::rotate_y(30.0) * Mat4::rotate_z(20.0);
+    for r in 0..3 {
+        for c in 0..3 {
+            assert!((g.m.0[r][c] - want.0[r][c]).abs() < 1e-9, "row {r} col {c}: {:?} vs {:?}", g.m.0, want.0);
+        }
+    }
+}
+
 #[test]
 fn keyframed_selector_animates() {
     let (mut p, cid, comp) = setup(400, 200);
@@ -567,6 +598,7 @@ fn touching_glyphs_join_without_a_seam() {
             fill,
             stroke: [0.0; 4],
             stroke_width: 0.0,
+            join: effectcraft_path::Join::Miter,
             bold: 0.0,
             apply_fill: true,
             char_index: 0,
@@ -637,6 +669,7 @@ fn faux_bold_under_a_non_uniform_scale() {
         fill: [1.0; 4],
         stroke: [0.0; 4],
         stroke_width: 0.0,
+        join: effectcraft_path::Join::Miter,
         bold: 2.0,
         apply_fill: true,
         char_index: 0,
diff --git a/crates/render/src/three_d/adv/scene.rs b/crates/render/src/three_d/adv/scene.rs
index a97272434..64cb4b579 100644
--- a/crates/render/src/three_d/adv/scene.rs
+++ b/crates/render/src/three_d/adv/scene.rs
@@ -572,7 +572,7 @@ pub fn extruded_meshes(ctx: &EvalCtx, layer: &Layer, p: &model::extrude::Extrude
                         groups.push((vec![g.local.clone()], c, g.m, usize::from(!stroke_on_top), g.xf.surface_colors(c)));
                     }
                     if g.stroke_width > 0.0 && g.stroke[3] * op > 0.0 {
-                        let st = effectcraft_path::StrokeStyle { width: g.stroke_width, join: effectcraft_path::Join::Round, ..Default::default() };
+                        let st = effectcraft_path::StrokeStyle { width: g.stroke_width, join: g.join, ..Default::default() };
                         if let Some(region) = crate::shapes::stroke_region(std::slice::from_ref(&g.local), &st) {
                             let c = [g.stroke[0], g.stroke[1], g.stroke[2], g.stroke[3] * op];
                             groups.push((vec![region], c, g.m, usize::from(stroke_on_top), g.xf.surface_colors(c)));
@@ -857,8 +857,8 @@ fn emit_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, b: &mut Bu
     if layer.environment || layer.switches.adjustment || ctx.opacity(layer) <= 0.0 || !layer.has_video() {
         return;
     }
-    if let Some(item) = r.collapsed(ctx, layer) {
-        collapsed_layer(r, ctx, layer, item, b);
+    if let Some(collapsed) = r.collapsed(ctx, layer) {
+        collapsed_layer(r, ctx, layer, &collapsed, b);
     } else if layer.source.is_model() {
         model_layer(r, ctx, layer, b);
     } else if matches!(layer.source, LayerSource::Text | LayerSource::Shape)
@@ -874,9 +874,9 @@ fn emit_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, b: &mut Bu
 /// (meshes, extrusions, cards) placed by the precomp layer's world transform, so they
 /// intersect, occlude and shadow the parent's layers. Nested 2D layers lie on the precomp
 /// layer's plane; nested lights and cameras are ignored (the parent's light the scene).
-fn collapsed_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, item: effectcraft_project::ItemId, b: &mut Builder) {
+fn collapsed_layer<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &Layer, collapsed: &crate::Collapsed, b: &mut Builder) {
     let op = ctx.opacity(layer) as f32 * r.opacity_mul();
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, op) else { return };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, op) else { return };
     let saved = b.outer;
     b.outer = saved * ctx.world_matrix(layer);
     let t = nctx.time;
diff --git a/crates/render/src/three_d/adv/tests.rs b/crates/render/src/three_d/adv/tests.rs
index 6e626ad0d..627e4e291 100644
--- a/crates/render/src/three_d/adv/tests.rs
+++ b/crates/render/src/three_d/adv/tests.rs
@@ -370,7 +370,16 @@ fn extruded_text_renders_as_a_mesh() {
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
         set(l, "transform/rotationY", Value::Scalar(40.0));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -409,7 +418,16 @@ fn shape_surface_items_colour_the_extruded_surfaces() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(40.0));
         set(l, "transform/position", Value::Vec3([100.0, 100.0, 0.0]));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -445,7 +463,16 @@ fn text_animators_colour_the_extruded_surfaces() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(30.0));
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
@@ -643,7 +670,16 @@ fn extruded_strokes_render_as_bevelled_meshes() {
         set(l, "geometryOptions/extrusionDepth", Value::Scalar(20.0));
         set(l, "geometryOptions/bevelStyle", Value::Enum(1));
     });
-    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
+    let ctx = crate::EvalCtx {
+        project: &p,
+        comp_id: cid,
+        comp: p.comp(cid).unwrap(),
+        time: Tick::ZERO,
+        expr: None,
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let l = &ctx.comp.layers[0];
     let params = scene::extrusion_params(&ctx, l).unwrap();
     let meshes = scene::extruded_meshes(&ctx, l, &params);
diff --git a/crates/render/src/three_d/bokeh.rs b/crates/render/src/three_d/bokeh.rs
index 12bcbcf37..098f095d0 100644
--- a/crates/render/src/three_d/bokeh.rs
+++ b/crates/render/src/three_d/bokeh.rs
@@ -289,16 +289,24 @@ pub fn progressive_blur(img: &Image, iris: &Iris, radius: &[f32]) -> Image {
         return bokeh_blur(img, iris, levels[0] as f64);
     }
     let (lo, hi, n) = (levels[0], levels[levels.len() - 1], levels.len());
-    let blurred: Vec<Image> = levels.par_iter().map(|&r| bokeh_blur(img, iris, r as f64)).collect();
+    // A pixel blends only the two levels around its radius, so the levels are made in order and
+    // only that pair is held: peak memory stays a few images whatever the level count, rather
+    // than one image per level. Each level's blur is parallel over its rows.
     let mut out = Image::new(img.width, img.height);
-    out.data.par_iter_mut().enumerate().for_each(|(i, o)| {
-        let r = radius[i];
-        let f = ((r - lo) / (hi - lo) * (n - 1) as f32).clamp(0.0, (n - 1) as f32);
-        let k = (f.floor() as usize).min(n - 2);
-        let t = f - k as f32;
-        let (a, b) = (blurred[k].data[i], blurred[k + 1].data[i]);
-        *o = [0, 1, 2, 3].map(|c| a[c] + (b[c] - a[c]) * t);
-    });
+    let mut below = bokeh_blur(img, iris, lo as f64);
+    for (k, &r) in levels.iter().enumerate().skip(1) {
+        let above = bokeh_blur(img, iris, r as f64);
+        out.data.par_iter_mut().enumerate().for_each(|(i, o)| {
+            let f = ((radius[i] - lo) / (hi - lo) * (n - 1) as f32).clamp(0.0, (n - 1) as f32);
+            let kk = (f.floor() as usize).min(n - 2);
+            if kk + 1 == k {
+                let t = f - kk as f32;
+                let (a, b) = (below.data[i], above.data[i]);
+                *o = [0, 1, 2, 3].map(|c| a[c] + (b[c] - a[c]) * t);
+            }
+        });
+        below = above;
+    }
     out
 }
 
diff --git a/crates/render/src/three_d/camera.rs b/crates/render/src/three_d/camera.rs
index 5af8859d5..a927e2ceb 100644
--- a/crates/render/src/three_d/camera.rs
+++ b/crates/render/src/three_d/camera.rs
@@ -37,7 +37,8 @@ pub struct Dof {
 impl Dof {
     /// Circle-of-confusion diameter (comp pixels) for a point at camera depth `z`.
     pub fn coc(&self, z: f64) -> f64 {
-        if z <= NEAR || self.focus <= 0.0 {
+        // No defocus can be measured against a non-finite focus or depth, so it counts as in focus.
+        if !z.is_finite() || z <= NEAR || !self.focus.is_finite() || self.focus <= 0.0 {
             return 0.0;
         }
         self.aperture * (z - self.focus).abs() / z * self.blur_level
@@ -360,22 +361,27 @@ pub fn layer_camera(ctx: &EvalCtx, cam: &Layer) -> CameraState {
     let (eye, fwd, down) = layer_frame(ctx, cam);
     let opts = cam.props.sub("cameraOptions");
     let zoom = opts.map(|g| ctx.f(cam, g, "zoom", 1000.0)).unwrap_or(1000.0).max(1e-3);
-    let dof = opts.filter(|g| ctx.b(cam, g, "dof")).map(|g| Dof {
-        focus: ctx.f(cam, g, "focusDistance", zoom),
-        aperture: ctx.f(cam, g, "aperture", default_aperture(w)).max(0.0),
-        blur_level: ctx.f(cam, g, "blurLevel", 100.0).max(0.0) / 100.0,
-        iris: super::bokeh::Iris {
-            sides: super::bokeh::Iris::sides_of_shape(ctx.e(cam, g, "irisShape")),
-            rotation: ctx.f(cam, g, "irisRotation", 0.0),
-            roundness: ctx.f(cam, g, "irisRoundness", 0.0) / 100.0,
-            aspect: ctx.f(cam, g, "irisAspectRatio", 1.0).max(0.01),
-            fringe: ctx.f(cam, g, "irisDiffractionFringe", 0.0).max(0.0) / 100.0,
-        },
-        highlight: super::bokeh::Highlight {
-            gain: ctx.f(cam, g, "highlightGain", 0.0).clamp(0.0, 100.0) / 100.0,
-            threshold: ctx.f(cam, g, "highlightThreshold", 255.0).clamp(0.0, 255.0) / 255.0,
-            saturation: ctx.f(cam, g, "highlightSaturation", 0.0).clamp(0.0, 100.0) / 100.0,
-        },
+    let dof = opts.filter(|g| ctx.b(cam, g, "dof")).map(|g| {
+        // A non-finite Focus Distance would make every blur radius non-finite; use the value the
+        // property defaults to (the zoom plane) instead.
+        let focus = ctx.f(cam, g, "focusDistance", zoom);
+        Dof {
+            focus: if focus.is_finite() { focus } else { zoom },
+            aperture: ctx.f(cam, g, "aperture", default_aperture(w)).max(0.0),
+            blur_level: ctx.f(cam, g, "blurLevel", 100.0).max(0.0) / 100.0,
+            iris: super::bokeh::Iris {
+                sides: super::bokeh::Iris::sides_of_shape(ctx.e(cam, g, "irisShape")),
+                rotation: ctx.f(cam, g, "irisRotation", 0.0),
+                roundness: ctx.f(cam, g, "irisRoundness", 0.0) / 100.0,
+                aspect: ctx.f(cam, g, "irisAspectRatio", 1.0).max(0.01),
+                fringe: ctx.f(cam, g, "irisDiffractionFringe", 0.0).max(0.0) / 100.0,
+            },
+            highlight: super::bokeh::Highlight {
+                gain: ctx.f(cam, g, "highlightGain", 0.0).clamp(0.0, 100.0) / 100.0,
+                threshold: ctx.f(cam, g, "highlightThreshold", 255.0).clamp(0.0, 255.0) / 255.0,
+                saturation: ctx.f(cam, g, "highlightSaturation", 0.0).clamp(0.0, 100.0) / 100.0,
+            },
+        }
     });
     CameraState { view: basis_view(eye, fwd, down), eye, zoom, ortho: false, dof }
 }
diff --git a/crates/render/src/three_d/compose.rs b/crates/render/src/three_d/compose.rs
index 38ac5b962..d203cfa71 100644
--- a/crates/render/src/three_d/compose.rs
+++ b/crates/render/src/three_d/compose.rs
@@ -18,7 +18,7 @@ use std::sync::Arc;
 use effectcraft_color::{BlendMode, blend_pixel};
 use effectcraft_effects::Buf;
 use effectcraft_geom::{Mat3, Mat4, Vec3, vec3};
-use effectcraft_project::{Layer, LightKind, MatteKind};
+use effectcraft_project::{Layer, LightKind, MatteKind, limits};
 use effectcraft_raster::{Image, Px, hash_noise};
 use effectcraft_time::Tick;
 use rayon::prelude::*;
@@ -195,13 +195,13 @@ fn mb_samples(r: &Renderer, ctx: &EvalCtx, layer: &Layer) -> usize {
 }
 
 /// Prepare a layer (buffer, geometry, material). `None` when it shows nothing.
-pub(crate) fn prepare<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Option<Item<'a>> {
+pub(crate) fn prepare<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Option<Item<'a>> {
     let buf = r.blend_layer_buf(ctx, layer)?;
     prepare_with(r, ctx, layer, order, out, in_run, PlaneInput { buf, local: Mat4::IDENTITY })
 }
 
 /// Prepare a layer as planes: one per character for per-character 3D text, else one.
-pub(crate) fn prepare_all<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Vec<Item<'a>> {
+pub(crate) fn prepare_all<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Vec<Item<'a>> {
     if crate::text::per_char_3d(ctx, layer) {
         return crate::text::per_char_planes(ctx, layer, r.opts.scale)
             .into_iter()
@@ -218,7 +218,7 @@ struct PlaneInput {
 }
 
 /// Prepare the plane's geometry, motion samples and material.
-fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool, plane: PlaneInput) -> Option<Item<'a>> {
+fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'_>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool, plane: PlaneInput) -> Option<Item<'a>> {
     let PlaneInput { mut buf, local } = plane;
     if buf.img.is_empty() {
         return None;
@@ -287,12 +287,45 @@ fn prepare_with<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: us
 }
 
 /// Blur radius (buffer pixels) of every buffer pixel of a plane at `world` (layer → world), from
-/// its camera depth: the circle of confusion over the on-screen size of one layer pixel there.
-fn dof_radii(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf) -> Vec<f32> {
-    dof_radii_at(cam, dof, world, (buf.img.width as usize, buf.img.height as usize), buf.offset, buf.scale)
+/// its camera depth: the circle of confusion over the on-screen size of one layer pixel there, at
+/// most `cap` ([`dof_radius_cap`]).
+fn dof_radii(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf, cap: f64) -> Vec<f32> {
+    dof_radii_at(cam, dof, world, (buf.img.width as usize, buf.img.height as usize), buf.offset, buf.scale, cap)
 }
 
-fn dof_radii_at(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, (w, h): (usize, usize), offset: [f64; 2], scale: f64) -> Vec<f32> {
+/// Pixels a padded blur buffer may have: the ~16 million layer buffers are held to
+/// ([`crate::Renderer::raster_scale`]), or twice the buffer when that is larger, so a big buffer
+/// can still be blurred. The blur holds a few images of this size at once whatever its level
+/// count ([`super::bokeh::progressive_blur`]), so blurring a small plane costs no more memory than
+/// blurring a large layer.
+const DOF_PAD_BUDGET: f64 = 16.0e6;
+
+/// Comp pixels per buffer pixel below which a plane isn't blurred. Such a plane covers almost no
+/// screen area (a 0%-scaled layer, one at an extreme distance), while its radius in buffer
+/// pixels grows without bound as it shrinks: blurring it would cost the most for the least.
+const DOF_MIN_SCREEN_SCALE: f64 = 1e-3;
+
+/// The largest blur radius (buffer pixels) of a `w`×`h` buffer: the one whose padded copy just
+/// fits [`DOF_PAD_BUDGET`]. The circle of confusion has no bound of its own (a focus distance far
+/// beyond the scene, a near-zero layer scale), so memory sets the limit; ordinary bokeh stays far
+/// below it and is never clamped.
+pub(super) fn dof_radius_cap(dof: &super::camera::Dof, w: u32, h: u32) -> f64 {
+    let (w, h) = (w as f64, h as f64);
+    let budget = DOF_PAD_BUDGET.max(2.0 * w * h);
+    // (w + 2p)·(h + 2p) = budget, solved for the padding p.
+    let pad = (((w - h) * (w - h) + 4.0 * budget).sqrt() - (w + h)) / 4.0;
+    ((pad - 2.0) / iris_stretch(dof)).max(0.0)
+}
+
+pub(super) fn dof_radii_at(
+    cam: &CameraState,
+    dof: &super::camera::Dof,
+    world: Mat4,
+    (w, h): (usize, usize),
+    offset: [f64; 2],
+    scale: f64,
+    cap: f64,
+) -> Vec<f32> {
     let s = scale.max(1e-9);
     let sx = world.apply_vec(vec3(1.0, 0.0, 0.0)).length().max(1e-9);
     let at = |x: f64, y: f64| cam.depth(world.apply(vec3((x - offset[0]) / s, (y - offset[1]) / s, 0.0)));
@@ -306,31 +339,48 @@ fn dof_radii_at(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, (w, h)
             if z <= super::camera::NEAR {
                 continue;
             }
-            // coc · ½ / (zoom / z · sx) · scale
-            *o = (dof.coc(z) * 0.5 * z / (cam.zoom * sx) * s) as f32;
+            // coc · ½ / (zoom / z · sx) · scale. Infinity clamps to the cap like any large radius,
+            // so the blur keeps growing with defocus; only NaN, which has no defocus, stays sharp.
+            let r = dof.coc(z) * 0.5 * z / (cam.zoom * sx) * s;
+            *o = if r.is_nan() || cam.zoom * sx / (z * s) < DOF_MIN_SCREEN_SCALE { 0.0 } else { r.min(cap) as f32 };
         }
     });
     out
 }
 
+/// How much the iris' aspect ratio stretches a blur radius along its longer axis.
+fn iris_stretch(dof: &super::camera::Dof) -> f64 {
+    let a = dof.iris.aspect.clamp(0.01, 100.0).sqrt();
+    a.max(1.0 / a)
+}
+
 /// The padding [`dof_blur`] gives a buffer whose largest blur radius is `rmax`.
 fn dof_pad(dof: &super::camera::Dof, rmax: f64) -> u32 {
-    let a = dof.iris.aspect.clamp(0.01, 100.0).sqrt().max(1.0 / dof.iris.aspect.clamp(0.01, 100.0).sqrt());
-    (rmax * a).ceil() as u32 + 2
+    ((rmax * iris_stretch(dof)).ceil() as u32).saturating_add(2)
+}
+
+/// The size of `img` padded by `pad` on every side, or `None` past [`limits::MAX_SIZE`] on a side:
+/// [`DOF_PAD_BUDGET`] bounds the area, so a long thin buffer could still outgrow a side.
+fn padded_size(img: &Image, pad: u32) -> Option<(u32, u32)> {
+    let grow = |n: u32| n.saturating_add(pad.saturating_mul(2));
+    let (w, h) = (grow(img.width), grow(img.height));
+    (w <= limits::MAX_SIZE && h <= limits::MAX_SIZE).then_some((w, h))
 }
 
 /// [`dof_blur`] planned for an accelerator: the padding, radius map and levels, and the padded
 /// buffer's layer-space bounds. `None` when nothing blurs.
 fn dof_plan(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf) -> Option<(PlaneDof, [f64; 4])> {
-    let radii = dof_radii(cam, dof, world, buf);
+    let cap = dof_radius_cap(dof, buf.img.width, buf.img.height);
+    let radii = dof_radii(cam, dof, world, buf, cap);
     let rmax = radii.iter().copied().fold(0.0f32, f32::max) as f64;
     if rmax <= 0.3 {
         return None;
     }
     let pad = dof_pad(dof, rmax);
-    let (w, h) = (buf.img.width as usize + 2 * pad as usize, buf.img.height as usize + 2 * pad as usize);
+    let (wp, hp) = padded_size(&buf.img, pad)?;
+    let (w, h) = (wp as usize, hp as usize);
     let offset = [buf.offset[0] + pad as f64, buf.offset[1] + pad as f64];
-    let radius = dof_radii_at(cam, dof, world, (w, h), offset, buf.scale);
+    let radius = dof_radii_at(cam, dof, world, (w, h), offset, buf.scale, cap);
     let levels = super::bokeh::blur_levels(&radius)?;
     let s = buf.scale.max(1e-9);
     let bounds = [-offset[0] / s, -offset[1] / s, (w as f64 - offset[0]) / s, (h as f64 - offset[1]) / s];
@@ -339,16 +389,20 @@ fn dof_plan(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: &Buf)
 
 /// Depth of field for one plane: highlights boosted, then a bokeh-shaped blur by depth.
 fn dof_blur(cam: &CameraState, dof: &super::camera::Dof, world: Mat4, buf: Arc<Buf>) -> Arc<Buf> {
-    let radii = dof_radii(cam, dof, world, &buf);
+    let cap = dof_radius_cap(dof, buf.img.width, buf.img.height);
+    let radii = dof_radii(cam, dof, world, &buf, cap);
     let rmax = radii.iter().copied().fold(0.0f32, f32::max) as f64;
     if rmax <= 0.3 {
         return buf;
     }
     let pad = dof_pad(dof, rmax);
+    if padded_size(&buf.img, pad).is_none() {
+        return buf;
+    }
     let mut padded = buf.img.padded(pad);
     super::bokeh::boost_highlights(&mut padded, &dof.highlight);
     let pbuf = Buf { img: padded, offset: [buf.offset[0] + pad as f64, buf.offset[1] + pad as f64], scale: buf.scale };
-    let pr = dof_radii(cam, dof, world, &pbuf);
+    let pr = dof_radii(cam, dof, world, &pbuf, cap);
     // The (cached, shared) layer buffer stays untouched; the blurred copy is per frame.
     Arc::new(Buf { img: super::bokeh::progressive_blur(&pbuf.img, &dof.iris, &pr), offset: pbuf.offset, scale: pbuf.scale })
 }
@@ -449,8 +503,8 @@ fn gather<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, run: &[&'a Layer], out: (u32,
         .flat_map_iter(|(i, l)| {
             // Stack order with room for a collapsed precomp's layers in between.
             let i = i * 1024;
-            if let Some(item) = r.collapsed(ctx, l) {
-                return collapsed_items(r, ctx, l, item, i, out);
+            if let Some(collapsed) = r.collapsed(ctx, l) {
+                return collapsed_items(r, ctx, l, &collapsed, i, out);
             }
             let mut its = prepare_all(r, ctx, l, i, out, true);
             if !its.is_empty() {
@@ -483,20 +537,13 @@ fn gather<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, run: &[&'a Layer], out: (u32,
 /// 3D space (world = precomp layer's world × nested world), depth-sorted with the run, so they
 /// intersect the parent's 3D layers; nested 2D layers lie on the precomp layer's plane in stack
 /// order. (Nested adjustment layers are skipped here.)
-fn collapsed_items<'a>(
-    r: &Renderer<'a>,
-    ctx: &EvalCtx<'a>,
-    layer: &'a Layer,
-    item: effectcraft_project::ItemId,
-    order: usize,
-    out: (u32, u32),
-) -> Vec<Item<'a>> {
+fn collapsed_items<'a>(r: &Renderer<'a>, ctx: &EvalCtx<'a>, layer: &'a Layer, collapsed: &crate::Collapsed, order: usize, out: (u32, u32)) -> Vec<Item<'a>> {
     let op = ctx.opacity(layer) as f32 * r.opacity_mul();
-    let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, op) else { return vec![] };
+    let Some((sub, nctx)) = r.collapse_into(ctx, layer, collapsed, op) else { return vec![] };
     let t = nctx.time;
-    let any_solo = nctx.comp.any_solo();
-    let nested: Vec<&'a Layer> = nctx
-        .comp
+    let Some(nc) = r.project.comp(collapsed.item) else { return vec![] };
+    let any_solo = nc.any_solo();
+    let nested: Vec<&'a Layer> = nc
         .layers
         .iter()
         .rev()
@@ -863,7 +910,7 @@ pub(crate) fn aux_pass(r: &Renderer, ctx: &EvalCtx) -> effectcraft_raster::AuxCh
                     if nv[2] > 0.0 {
                         nv = nv.map(|v| -v);
                     }
-                    let (sw, sh) = crate::source_size(r.project, it.layer);
+                    let (sw, sh) = ctx.source_size(it.layer);
                     let size = if sw == 0 { [ctx.comp.width as f64, ctx.comp.height as f64] } else { [sw as f64, sh as f64] };
                     (number(it.layer), source_id(it.layer), crypto_hash(&it.layer.name), crypto_hash(&source_name(it.layer)), nv, size)
                 })
diff --git a/crates/render/src/three_d/tests.rs b/crates/render/src/three_d/tests.rs
index 5e20b4635..026929623 100644
--- a/crates/render/src/three_d/tests.rs
+++ b/crates/render/src/three_d/tests.rs
@@ -13,10 +13,15 @@ const W: u32 = 200;
 const H: u32 = 100;
 
 fn setup() -> (Project, ItemId, Comp) {
+    setup_sized(W, H)
+}
+
+/// [`setup`] with a `w`×`h` comp.
+fn setup_sized(w: u32, h: u32) -> (Project, ItemId, Comp) {
     let mut p = Project::default();
     // Exact float maths; 8/16 bpc quantisation has its own tests (tests_color).
     p.settings.bit_depth = effectcraft_project::BitDepth::Bpc32;
-    let comp = Comp::new(W, H, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
+    let comp = Comp::new(w, h, FrameRate::FPS_30, Tick::from_seconds_f64(2.0));
     let cid = p.add_item("Comp", Label::Sandstone, None, ItemKind::Comp(comp.clone().into()));
     (p, cid, comp)
 }
@@ -374,7 +379,7 @@ fn shadow_diffusion_is_a_soft_ramp_not_copies() {
 // ---------------------------------------------------------------- cameras
 
 fn camera(p: &mut Project, comp: &Comp) -> Layer {
-    build::layer(p, comp, "Camera", LayerSource::Camera, (W, H), None)
+    build::layer(p, comp, "Camera", LayerSource::Camera, (comp.width, comp.height), None)
 }
 
 #[test]
@@ -450,9 +455,155 @@ fn depth_of_field_blurs_out_of_focus_layers() {
     assert!(b.get(66, 50)[3] > 0.01);
 }
 
+/// A non-finite Focus Distance doesn't reach the blur: the camera focuses on the property's
+/// default plane (`zoom`) instead.
+#[test]
+fn dof_falls_back_when_focus_distance_is_not_finite() {
+    for bad in [f64::NAN, f64::INFINITY, f64::NEG_INFINITY] {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(bad));
+        let s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let cp = p.comp(cid).unwrap();
+        let ctx = crate::EvalCtx::new(&p, cid, cp, Tick::ZERO);
+        let cs = crate::three_d::camera::layer_camera(&ctx, &cp.layers[0]);
+        let f = cs.dof.unwrap().focus;
+        assert!((f - zoom()).abs() < 1e-9, "{bad}: evaluated to {f}, expected the fallback to zoom {}", zoom());
+        // The z = 0 plane is in focus: hard edge, finite pixels.
+        let img = render(&p, cid);
+        assert!(img.get(71, 50)[3] > 0.99 && img.get(69, 50)[3] < 0.01, "{bad}: the edge should be hard");
+        assert!(img.data.iter().all(|px| px.iter().all(|c| c.is_finite())), "{bad}: non-finite pixels");
+    }
+}
+
+/// The Classic 3D blur stays bounded for degenerate inputs: a 0%-scaled 3D layer off the focal
+/// plane (e.g. the first frame of a scale-in) or a huge but finite Focus Distance asks for a
+/// radius of billions of buffer pixels, whose padded buffer can't be allocated.
+#[test]
+fn dof_blur_radius_is_bounded_for_degenerate_inputs() {
+    let scene = |focus: f64, scale: f64| {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(focus));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        render(&p, cid)
+    };
+    let finite = |img: &effectcraft_raster::Image| img.data.iter().all(|px| px.iter().all(|c| c.is_finite()));
+    // A 0%-scaled layer 10 px off the focal plane: an ordinary defocus times 1/sx (sx = 1e-9).
+    assert!(finite(&scene(zoom() + 10.0, 0.0)), "zero-scaled: non-finite pixels");
+    // Huge but finite Focus Distances (typed in, or a large expression result): the blur is as
+    // large as the buffer budget allows, never refused (which would render the layer sharp).
+    // 1e307 overflows the circle of confusion itself to infinity: still the largest blur.
+    for focus in [1.0e12, 1.0e307] {
+        let img = scene(focus, 100.0);
+        assert!(finite(&img), "focus {focus:e}: non-finite pixels");
+        assert!(img.get(100, 50)[3] < 0.5, "focus {focus:e}: the layer should be spread out, not sharp ({})", img.get(100, 50)[3]);
+    }
+}
+
+/// The blur radius map of a plane: a 0%-scaled plane is degenerate on screen and isn't blurred;
+/// any other radius stays within the buffer budget's cap.
+#[test]
+fn dof_radii_skip_degenerate_planes_and_respect_the_cap() {
+    let radii = |focus: f64, scale: f64| {
+        let (mut p, cid, comp) = setup();
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(60.0));
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(focus));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 60, 60, [100.0, 50.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let cp = p.comp(cid).unwrap();
+        let ctx = crate::EvalCtx::new(&p, cid, cp, Tick::ZERO);
+        let cs = super::camera::layer_camera(&ctx, &cp.layers[0]);
+        let dof = cs.dof.unwrap();
+        let cap = super::compose::dof_radius_cap(&dof, 60, 60);
+        (super::compose::dof_radii_at(&cs, &dof, ctx.world_matrix(&cp.layers[1]), (60, 60), [0.0; 2], 1.0, cap), cap)
+    };
+    let (r, _) = radii(zoom() + 10.0, 0.0);
+    assert!(r.iter().all(|&r| r == 0.0), "a 0%-scaled plane is not blurred");
+    let (r, cap) = radii(1.0e12, 100.0);
+    assert!(cap > 1000.0, "a 60×60 buffer may blur by well over 1000 px: {cap}");
+    assert!(r.iter().all(|&r| r as f64 <= cap && r as f64 > cap - 1.0), "huge focus: every radius at the cap {cap}");
+}
+
+/// Two layers that look the same on screen (400×100 at 100%, 1600×400 at 25%) at the same depth
+/// blur by the same amount on screen: the radius bound must not depend on the layer's scale.
+#[test]
+fn dof_blur_is_independent_of_layer_scale() {
+    let ramp = |w: u32, h: u32, scale: f64| {
+        let (mut p, cid, comp) = setup_sized(800, 400);
+        let zoom = 800.0 * 50.0 / 36.0;
+        let mut cam = camera(&mut p, &comp);
+        set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+        set(&mut cam, "cameraOptions/aperture", Value::Scalar(200.0));
+        // coc = aperture·|z − f| / z: a 40 px comp radius on the z = 0 plane (depth = zoom).
+        set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(zoom + 2.0 * 40.0 * zoom / 200.0));
+        let mut s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], w, h, [400.0, 200.0, 0.0]);
+        set(&mut s, "transform/scale", Value::Vec3([scale, scale, 100.0]));
+        push(&mut p, cid, cam);
+        push(&mut p, cid, s);
+        let img = render(&p, cid);
+        soft_count(&img, (0..400).map(|x| (x, 200)))
+    };
+    let (full, quarter) = (ramp(400, 100, 100.0), ramp(1600, 400, 25.0));
+    assert!(full > 60, "the out-of-focus edge should be soft: {full}");
+    assert!(full.abs_diff(quarter) <= 2, "same on-screen layer, same depth: {full} px at 100% vs {quarter} px at 25%");
+}
+
+/// The same frame at Full and Half resolution shows the same blur (in comp pixels). The radius
+/// (~100 px) is large so that any bound that depends on the resolution would show.
+#[test]
+fn dof_blur_matches_across_render_resolutions() {
+    let (mut p, cid, comp) = setup_sized(800, 400);
+    let zoom = 800.0 * 50.0 / 36.0;
+    let mut cam = camera(&mut p, &comp);
+    set(&mut cam, "cameraOptions/dof", Value::Bool(true));
+    set(&mut cam, "cameraOptions/aperture", Value::Scalar(200.0));
+    set(&mut cam, "cameraOptions/focusDistance", Value::Scalar(2.0 * zoom));
+    let s = solid3(&mut p, &comp, [1.0, 1.0, 1.0], 400, 100, [400.0, 200.0, 0.0]);
+    push(&mut p, cid, cam);
+    push(&mut p, cid, s);
+    let ramp = |scale: f64| {
+        let img = render_frame(&p, cid, Tick::ZERO, scale);
+        let (w, h) = (img.width as i64, img.height as i64);
+        soft_count(&img, (0..w / 2).map(|x| (x, h / 2))) as f64 / scale
+    };
+    let (full, half) = (ramp(1.0), ramp(0.5));
+    assert!(full > 150.0, "a ~100 px radius must not be clamped: {full} comp px");
+    assert!((full - half).abs() <= 4.0, "Full {full} vs Half {half} comp px");
+}
+
+/// `Dof::coc` treats a non-finite focus or depth as in focus.
+#[test]
+fn dof_coc_is_zero_for_non_finite_inputs() {
+    let d = |focus: f64| super::camera::Dof { focus, aperture: 50.0, blur_level: 1.0, iris: Default::default(), highlight: Default::default() };
+    for bad in [f64::NAN, f64::INFINITY, f64::NEG_INFINITY] {
+        assert_eq!(d(bad).coc(500.0), 0.0, "focus {bad}");
+        assert_eq!(d(400.0).coc(bad), 0.0, "depth {bad}");
+    }
+    assert!(d(400.0).coc(500.0) > 0.0);
+}
+
+/// Pixels among `pts` whose alpha is strictly between 0.05 and 0.95.
+fn soft_count(img: &effectcraft_raster::Image, pts: impl Iterator<Item = (i64, i64)>) -> usize {
+    pts.filter(|&(x, y)| (0.05..0.95).contains(&img.get(x, y)[3])).count()
+}
+
 /// Pixels in column `x` whose alpha is strictly between 0.05 and 0.95.
 fn soft_px(img: &effectcraft_raster::Image, x: i64) -> usize {
-    (0..img.height as i64).filter(|&y| (0.05..0.95).contains(&img.get(x, y)[3])).count()
+    soft_count(img, (0..img.height as i64).map(|y| (x, y)))
 }
 
 #[test]
diff --git a/crates/script/src/matchnames.rs b/crates/script/src/matchnames.rs
index b64aaab37..3dd717aa8 100644
--- a/crates/script/src/matchnames.rs
+++ b/crates/script/src/matchnames.rs
@@ -90,6 +90,44 @@ pub fn stroke_dash(name: &str) -> Option<&'static str> {
 
 const TEXT_ANIMATOR: &[(&str, &str)] = &[("selectors", "ADBE Text Selectors"), ("properties", "ADBE Text Animator Properties")];
 
+/// Animator property ids and their stable After Effects scripting names. Shared by lookup,
+/// `.matchName`, and `addProperty` so the same property has one name in every direction.
+pub const TEXT_ANIMATOR_PROPERTIES: &[(&str, &str)] = &[
+    ("anchor", "ADBE Text Anchor Point 3D"),
+    ("position", "ADBE Text Position 3D"),
+    ("scale", "ADBE Text Scale 3D"),
+    ("skew", "ADBE Text Skew"),
+    ("rotation", "ADBE Text Rotation"),
+    ("opacity", "ADBE Text Opacity"),
+    ("fillColor", "ADBE Text Fill Color"),
+    ("fillHue", "ADBE Text Fill Hue"),
+    ("fillSaturation", "ADBE Text Fill Saturation"),
+    ("fillBrightness", "ADBE Text Fill Brightness"),
+    ("fillOpacity", "ADBE Text Fill Opacity"),
+    ("strokeColor", "ADBE Text Stroke Color"),
+    ("strokeHue", "ADBE Text Stroke Hue"),
+    ("strokeSaturation", "ADBE Text Stroke Saturation"),
+    ("strokeBrightness", "ADBE Text Stroke Brightness"),
+    ("strokeOpacity", "ADBE Text Stroke Opacity"),
+    ("strokeWidth", "ADBE Text Stroke Width"),
+    ("tracking", "ADBE Text Tracking Amount"),
+    ("lineAnchor", "ADBE Text Line Anchor"),
+    ("lineSpacing", "ADBE Text Line Spacing"),
+    ("characterOffset", "ADBE Text Character Offset"),
+    ("characterValue", "ADBE Text Character Replace"),
+    ("blur", "ADBE Text Blur"),
+];
+
+/// Companion properties that exist below an animator but are not kinds `addProperty` accepts:
+/// they come with Tracking (Track Type), Skew (Skew Axis) and per-character 3D Rotation
+/// (X and Y Rotation). Lookup and `.matchName` know them; `addProperty` does not.
+pub const TEXT_ANIMATOR_COMPANIONS: &[(&str, &str)] = &[
+    ("trackingType", "ADBE Text Track Type"),
+    ("skewAxis", "ADBE Text Skew Axis"),
+    ("rotationX", "ADBE Text Rotation X"),
+    ("rotationY", "ADBE Text Rotation Y"),
+];
+
 const TEXT_SELECTORS: &[(&str, &str)] =
     &[("rangeSelector", "ADBE Text Selector"), ("wigglySelector", "ADBE Text Wiggly Selector"), ("expressionSelector", "ADBE Text Expressible Selector")];
 
@@ -487,6 +525,9 @@ pub fn node(chain: &[&Node]) -> String {
         "text" if pid == "animators" => "ADBE Text Animator".into(),
         "text" if pid == "selectors" => find(TEXT_SELECTORS, id).map(str::to_string).unwrap_or_else(own),
         "text" if pid == "rangeSelector" => find(TEXT_RANGE_SELECTOR, id).map(str::to_string).unwrap_or_else(own),
+        "text" if pid == "properties" && chain.len() == 5 && chain.get(1).is_some_and(|n| n.match_id() == "animators") => {
+            find(TEXT_ANIMATOR_PROPERTIES, id).or_else(|| find(TEXT_ANIMATOR_COMPANIONS, id)).map(str::to_string).unwrap_or_else(own)
+        }
         "text" if grand.map(|g| g.match_id()) == Some("animators") => find(TEXT_ANIMATOR, id).map(str::to_string).unwrap_or_else(own),
         "cameraOptions" => find(CAMERA, id).map(str::to_string).unwrap_or_else(own),
         "lightOptions" => find(LIGHT, id).map(str::to_string).unwrap_or_else(own),
@@ -537,6 +578,30 @@ mod tests {
         assert_eq!(shape_kind("nope"), None);
     }
 
+    #[test]
+    fn text_animator_property_names_are_canonical_and_scoped() {
+        let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));
+        let (text, animators, animator, properties) = (n("text"), n("animators"), n("animator"), n("properties"));
+        for (id, name) in TEXT_ANIMATOR_PROPERTIES {
+            let prop = n(id);
+            assert_eq!(node(&[&text, &animators, &animator, &properties, &prop]), *name);
+            assert_eq!(node(&[&properties, &prop]), *id, "an unrelated Properties group keeps its own ids");
+        }
+    }
+
+    /// #1063: the companions an animator property brings (Track Type, Skew Axis, X / Y Rotation)
+    /// have their After Effects names too, though `addProperty` does not accept them.
+    #[test]
+    fn text_animator_companions_have_after_effects_names() {
+        let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));
+        let (text, animators, animator, properties) = (n("text"), n("animators"), n("animator"), n("properties"));
+        for (id, name) in TEXT_ANIMATOR_COMPANIONS {
+            let prop = n(id);
+            assert_eq!(node(&[&text, &animators, &animator, &properties, &prop]), *name);
+            assert!(!TEXT_ANIMATOR_PROPERTIES.iter().any(|(k, m)| k == id || m == name), "{id} is not an addProperty kind");
+        }
+    }
+
     #[test]
     fn text_range_selector_names() {
         let n = |m: &str| Node::from(effectcraft_project::PropGroup::new(1, m, m));
diff --git a/crates/script/src/model.rs b/crates/script/src/model.rs
index 23356c064..258a6de2d 100644
--- a/crates/script/src/model.rs
+++ b/crates/script/src/model.rs
@@ -743,36 +743,12 @@ fn resolve_add(s: &Session, a: &J) -> R {
 /// A text animator property (`layer.addTextAnimatorProperty` key) from an After Effects match
 /// name or a display name.
 fn text_animator_property(name: &str) -> Option<&'static str> {
-    const AE: &[(&str, &str)] = &[
-        ("ADBE Text Anchor Point 3D", "anchor"),
-        ("ADBE Text Position 3D", "position"),
-        ("ADBE Text Scale 3D", "scale"),
-        ("ADBE Text Skew", "skew"),
-        ("ADBE Text Rotation", "rotation"),
-        ("ADBE Text Opacity", "opacity"),
-        ("ADBE Text Fill Color", "fillColor"),
-        ("ADBE Text Fill Hue", "fillHue"),
-        ("ADBE Text Fill Saturation", "fillSaturation"),
-        ("ADBE Text Fill Brightness", "fillBrightness"),
-        ("ADBE Text Fill Opacity", "fillOpacity"),
-        ("ADBE Text Stroke Color", "strokeColor"),
-        ("ADBE Text Stroke Hue", "strokeHue"),
-        ("ADBE Text Stroke Saturation", "strokeSaturation"),
-        ("ADBE Text Stroke Brightness", "strokeBrightness"),
-        ("ADBE Text Stroke Opacity", "strokeOpacity"),
-        ("ADBE Text Stroke Width", "strokeWidth"),
-        ("ADBE Text Tracking Amount", "tracking"),
-        ("ADBE Text Line Anchor", "lineAnchor"),
-        ("ADBE Text Line Spacing", "lineSpacing"),
-        ("ADBE Text Character Offset", "characterOffset"),
-        ("ADBE Text Character Replace", "characterValue"),
-        ("ADBE Text Blur", "blur"),
-    ];
-    if let Some((_, k)) = AE.iter().find(|(m, _)| m.eq_ignore_ascii_case(name)) {
+    let table = matchnames::TEXT_ANIMATOR_PROPERTIES;
+    if let Some((k, _)) = table.iter().find(|(_, m)| m.eq_ignore_ascii_case(name)) {
         return Some(k);
     }
     let n = loose(name);
-    AE.iter().map(|(_, k)| *k).find(|k| loose(k) == n || (n == "anchorpoint" && *k == "anchor") || (n == "trackingamount" && *k == "tracking"))
+    table.iter().map(|(k, _)| *k).find(|k| loose(k) == n || (n == "anchorpoint" && *k == "anchor") || (n == "trackingamount" && *k == "tracking"))
 }
 
 /// `app.findMenuCommandId(name)`: 1-based index of the command whose label matches (menu items
diff --git a/crates/script/src/prelude.js b/crates/script/src/prelude.js
index f012ce128..a33714314 100644
--- a/crates/script/src/prelude.js
+++ b/crates/script/src/prelude.js
@@ -734,9 +734,8 @@ PropertyGroup.prototype.addProperty = function (name) {
   } else if (r.kind === "animator") {
     uid = __call("layer.addTextAnimator", { comp: L.__comp, layer: L.__id, properties: [] }).animator;
   } else if (r.kind === "animatorProperty") {
-    var before = this.numProperties;
-    __call("layer.addTextAnimatorProperty", { comp: L.__comp, layer: L.__id, animator: r.animator, property: r.property });
-    return this.property(before + 1);
+    var added = __call("layer.addTextAnimatorProperty", { comp: L.__comp, layer: L.__id, animator: r.animator, property: r.property });
+    return this.property(added.index);
   } else if (r.kind === "selector") {
     var n0 = this.numProperties;
     __call("layer.addTextSelector", { comp: L.__comp, layer: L.__id, animator: r.animator, kind: r.selector });
diff --git a/crates/script/src/tests.rs b/crates/script/src/tests.rs
index a2f674d0a..875885c11 100644
--- a/crates/script/src/tests.rs
+++ b/crates/script/src/tests.rs
@@ -1719,6 +1719,50 @@ fn layer_property_resolves_transform_and_source_text_shortcuts() {
     assert_eq!(layer(c, "s").props.prop("transform/opacity").unwrap().value, KV::Scalar(25.0));
 }
 
+/// A text animator property added by its After Effects name is the one asked for, not its Tracking
+/// Type companion, and it can be found again by that name (#1063).
+#[test]
+fn scripted_text_animator_property_is_the_one_asked_for() {
+    let mut s = session();
+    let o = ok(
+        &mut s,
+        r#"
+        var c = app.project.items.addComp("Track", 960, 300, 1, 3, 30);
+        var t = c.layers.addText("MOVARA");
+        var a = t.property("ADBE Text Properties").property("ADBE Text Animators").addProperty("ADBE Text Animator");
+        var props = a.property("ADBE Text Animator Properties");
+        var added = props.addProperty("ADBE Text Tracking Amount");
+        added.setValue(20);
+        [added.name, props.property("ADBE Text Tracking Amount").value, props.property("ADBE Text Tracking Amount").name,
+         added.matchName, props.property(added.matchName).propertyIndex]
+        "#,
+    );
+    assert_eq!(o.result, json!(["Tracking Amount", 20, "Tracking Amount", "ADBE Text Tracking Amount", 2]));
+}
+
+/// The companion properties added with Tracking and Skew are found by their After Effects names,
+/// but cannot be added on their own (#1063).
+#[test]
+fn text_animator_companion_properties_resolve_by_name() {
+    let mut s = session();
+    let o = ok(
+        &mut s,
+        r#"
+        var c = app.project.items.addComp("Track", 960, 300, 1, 3, 30);
+        var t = c.layers.addText("MOVARA");
+        var props = t.property("ADBE Text Properties").property("ADBE Text Animators").addProperty("ADBE Text Animator").property("ADBE Text Animator Properties");
+        props.addProperty("ADBE Text Tracking Amount");
+        props.addProperty("ADBE Text Skew");
+        var type = props.property("ADBE Text Track Type");
+        var axis = props.property("ADBE Text Skew Axis");
+        var added = "";
+        try { props.addProperty("ADBE Text Track Type"); added = "added"; } catch (e) { added = "refused"; }
+        [type ? type.matchName : null, axis ? axis.matchName : null, added]
+        "#,
+    );
+    assert_eq!(o.result, json!(["ADBE Text Track Type", "ADBE Text Skew Axis", "refused"]));
+}
+
 /// #1936: an array whose length doesn't match the property's dimension is an error in After
 /// Effects, not a value to truncate or broadcast. Two values for a 3-D property stay legal.
 #[test]
diff --git a/crates/script/src/tests/ease_presets.rs b/crates/script/src/tests/ease_presets.rs
index 009cc59c6..f075250b2 100644
--- a/crates/script/src/tests/ease_presets.rs
+++ b/crates/script/src/tests/ease_presets.rs
@@ -608,3 +608,37 @@ fn presets_saved_by_the_old_core_panel_carry_over() {
     let win = open_panel(&mut s);
     assert_eq!(control(&mut s, win, "presets")["items"].as_array().unwrap().len(), 12);
 }
+
+/// #2465: the Linear preset sets Linear interpolation on every side it applies to, including the
+/// unused first-in and last-out sides; editing its speeds makes a Bezier curve.
+#[test]
+fn the_linear_preset_sets_linear_interpolation_and_edited_speeds_give_bezier() {
+    let store = Arc::new(MemoryConfig::default());
+    let mut s = session(&store);
+    let l = setup(&mut s);
+    animate(&mut s, l, "transform/opacity", &[(0.0, json!(0)), (1.0, json!(100)), (3.0, json!(20))]);
+    s.execute("prop.select", json!({"layer": l, "path": "transform/opacity"})).unwrap();
+    let win = open_panel(&mut s);
+    // Start from Bezier keys so Linear has something to restore.
+    ok(
+        &mut s,
+        r#"var p = app.project.activeItem.layer(1).transform.opacity, K = KeyframeInterpolationType;
+        for (var i = 1; i <= p.numKeys; i++) p.setInterpolationTypeAtKey(i, K.BEZIER, K.BEZIER);"#,
+    );
+    let op = prop(&s, l, "transform/opacity");
+    for (i, k) in op.keys.iter().enumerate() {
+        assert_eq!((k.in_interp, k.out_interp), (Interp::Bezier, Interp::Bezier), "initial key {i}");
+    }
+    let steps = s.history.undo.len();
+    set(&mut s, win, "presets", json!("Linear"));
+    assert_eq!(s.history.undo.len(), steps + 1, "one undo step");
+    let op = prop(&s, l, "transform/opacity");
+    for (i, k) in op.keys.iter().enumerate() {
+        assert_eq!((k.in_interp, k.out_interp), (Interp::Linear, Interp::Linear), "key {i}");
+    }
+    // Edited speeds make a custom Bezier curve even though Linear is still the selected preset.
+    select_keys(&mut s, l, &[("transform/opacity", 1.0)]);
+    apply_typed(&mut s, win, "In-Out", [33.0, 2.0, 33.0, 2.0]);
+    let k = &prop(&s, l, "transform/opacity").keys[1];
+    assert_eq!((k.in_interp, k.out_interp), (Interp::Bezier, Interp::Bezier));
+}
diff --git a/crates/script/src/tests/ui_more.rs b/crates/script/src/tests/ui_more.rs
index 228a58016..483d686ef 100644
--- a/crates/script/src/tests/ui_more.rs
+++ b/crates/script/src/tests/ui_more.rs
@@ -222,7 +222,16 @@ fn position_now(s: &Session, layer: u64) -> [f64; 2] {
     let cid = s.active_comp_id().unwrap();
     let comp = s.project.comp(cid).unwrap();
     let l = comp.layer(effectcraft_engine::project::LayerId(layer)).unwrap();
-    let ctx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: None };
+    let ctx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let v = ctx.value(l, l.props.prop("transform/position").unwrap()).components();
     [v[0], v[1]]
 }
diff --git a/crates/text/src/fonts.rs b/crates/text/src/fonts.rs
index a973335f4..a31a17124 100644
--- a/crates/text/src/fonts.rs
+++ b/crates/text/src/fonts.rs
@@ -707,14 +707,28 @@ const JAPANESE_FAMILIES: &[&str] = &[
 ];
 /// Han ideograph families for Simplified Chinese, in the order the platforms' own fallback tables
 /// prefer them (Windows, macOS, then the Linux/Noto names). Missing ones cost one name lookup each.
-const SIMPLIFIED_CHINESE_FAMILIES: &[&str] =
-    &["Microsoft YaHei", "SimSun", "PingFang SC", "Noto Sans CJK SC", "Noto Sans SC", "Source Han Sans SC", "WenQuanYi Micro Hei"];
+/// `Hiragino Sans GB`, `Heiti SC` and `Songti SC` are the Simplified faces a macOS install without
+/// the on-demand PingFang has (macOS 27 on an English install ships them, not PingFang): without
+/// them Chinese Han text fell through to the Japanese face and drew Japanese glyph forms (#453).
+const SIMPLIFIED_CHINESE_FAMILIES: &[&str] = &[
+    "Microsoft YaHei",
+    "SimSun",
+    "PingFang SC",
+    "Hiragino Sans GB",
+    "Heiti SC",
+    "Songti SC",
+    "STSong",
+    "Noto Sans CJK SC",
+    "Noto Sans SC",
+    "Source Han Sans SC",
+    "WenQuanYi Micro Hei",
+];
 /// The same for Traditional Chinese. The two scripts share almost all of their code points but not
 /// the glyph forms (`东` against `東`'s neighbours, `直`, `骨`), so one list for both drew a
 /// Traditional interface with Simplified forms - the faces do not differ in *coverage*, which is
 /// what the fallback search checks, so the script has to pick the list.
 const TRADITIONAL_CHINESE_FAMILIES: &[&str] =
-    &["Microsoft JhengHei", "MingLiU", "PingFang TC", "Heiti TC", "Hiragino Sans CNS", "Noto Sans CJK TC", "Noto Sans TC", "Source Han Sans TC"];
+    &["Microsoft JhengHei", "MingLiU", "PingFang TC", "Heiti TC", "Hiragino Sans CNS", "Songti TC", "Noto Sans CJK TC", "Noto Sans TC", "Source Han Sans TC"];
 const KOREAN_FAMILIES: &[&str] = &["Malgun Gothic", "Gulim", "Apple SD Gothic Neo", "Noto Sans CJK KR", "Noto Sans KR", "Source Han Sans KR", "NanumGothic"];
 /// The platforms' plain text families for the other scripts the bundled fonts lack, in the same
 /// order (Windows, macOS, then the Linux/Noto names).
diff --git a/crates/text/src/fonts/tests.rs b/crates/text/src/fonts/tests.rs
index 079a001e0..9a6ba365a 100644
--- a/crates/text/src/fonts/tests.rs
+++ b/crates/text/src/fonts/tests.rs
@@ -1,5 +1,14 @@
 use super::*;
 
+/// Run `test` again in a child process with `variable` set. The fixture faces below go into the
+/// process-global font database and its fallback caches, so only a process that runs one such test
+/// on its own can use them.
+#[cfg(not(target_arch = "wasm32"))]
+fn run_in_child(variable: &str, test: &str) {
+    let output = std::process::Command::new(std::env::current_exe().unwrap()).args(["--exact", test, "--nocapture"]).env(variable, "1").output().unwrap();
+    assert!(output.status.success(), "{}\n{}", String::from_utf8_lossy(&output.stdout), String::from_utf8_lossy(&output.stderr));
+}
+
 /// Concurrent language requests must neither choose another context's font nor reuse its
 /// cached family order. Synthetic fonts in a child process keep this independent of the host
 /// font installation and of other tests that exercise the process-global database/locale.
@@ -8,12 +17,7 @@ use super::*;
 fn cjk_requests_keep_their_language_and_cache_entries() {
     const CHILD: &str = "EFFECTCRAFT_TEST_ISOLATED_CJK";
     if std::env::var_os(CHILD).is_none() {
-        let output = std::process::Command::new(std::env::current_exe().unwrap())
-            .args(["--exact", "fonts::tests::cjk_requests_keep_their_language_and_cache_entries", "--nocapture"])
-            .env(CHILD, "1")
-            .output()
-            .unwrap();
-        assert!(output.status.success(), "{}\n{}", String::from_utf8_lossy(&output.stdout), String::from_utf8_lossy(&output.stderr));
+        run_in_child(CHILD, "fonts::tests::cjk_requests_keep_their_language_and_cache_entries");
         return;
     }
     let families = [("ja", "Yu Gothic"), ("zh-hans", "Microsoft YaHei"), ("zh-hant", "Microsoft JhengHei"), ("ko", "Malgun Gothic")];
@@ -71,6 +75,52 @@ fn cjk_requests_keep_their_language_and_cache_entries() {
     }
 }
 
+/// #453: with a Chinese interface, a Han ideograph that both a Chinese and a Japanese face cover
+/// must reach the installed Simplified Chinese family first, or Chinese text in a composition is
+/// drawn with Japanese glyph forms. Fixture faces named after the macOS families keep this
+/// independent of the host's fonts and of rendering. Before the fix the Simplified list named none
+/// of the macOS faces a stock install has, so the walk below reached the Japanese face - the
+/// regression this guards.
+#[test]
+#[cfg(not(target_arch = "wasm32"))]
+fn zh_hans_han_fallback_puts_the_chinese_family_first() {
+    const CHILD: &str = "EFFECTCRAFT_TEST_ZH_HANS_ORDER";
+    if std::env::var_os(CHILD).is_none() {
+        run_in_child(CHILD, "fonts::tests::zh_hans_han_fallback_puts_the_chinese_family_first");
+        return;
+    }
+    let mut ids = Vec::new();
+    {
+        let mut d = db().write().unwrap();
+        d.scanned = true; // This test process uses only bundled and synthetic fonts.
+        // The Japanese face is added first, so scan order cannot be what picks the Chinese one.
+        for family in ["Hiragino Sans", "Hiragino Sans GB"] {
+            let mut data = test_font(family);
+            let table = data[12..12 + 8 * 16].as_chunks::<16>().0.iter().find(|t| &t[..4] == b"cmap").unwrap();
+            let cmap = u32::from_be_bytes(table[8..12].try_into().unwrap()) as usize + 12;
+            // Map 页 to the fixture's triangle glyph instead of its private-use range.
+            for (offset, value) in [(16, '页' as u16), (24, '页' as u16), (30, 2u16.wrapping_sub('页' as u16))] {
+                data[cmap + offset..cmap + offset + 2].copy_from_slice(&value.to_be_bytes());
+            }
+            let data = Arc::new(data);
+            let names = read_faces_bytes(&data).into_iter().next().unwrap();
+            ids.push(push(&mut d, info_from(names, FaceData::Shared(data), "test")));
+        }
+    }
+    let &[japanese, chinese] = ids.as_slice() else { panic!("two fixture faces expected: {ids:?}") };
+    let base = resolve("Inter", "Regular").face;
+    assert!(face(japanese).has_char('页') && face(chinese).has_char('页'));
+    // The fallback list itself, before any coverage check: the Chinese family comes first for
+    // zh-hans and second for ja, whether or not either face can draw the probe.
+    let zh_hans: Vec<FaceId> = family_faces(FallbackScript::Han, &face(base), CjkLocale::Simplified).to_vec();
+    assert_eq!(zh_hans, [chinese, japanese], "zh-hans tries the Chinese family first");
+    let ja: Vec<FaceId> = family_faces(FallbackScript::Han, &face(base), CjkLocale::Japanese).to_vec();
+    assert_eq!(ja, [japanese, chinese], "ja keeps the Japanese family first");
+    // ...and the face a layout actually gets for the shared ideograph.
+    assert_eq!(face(fallback_for_locale('页', base, "zh-hans")).info.family, "Hiragino Sans GB");
+    assert_eq!(face(fallback_for_locale('页', base, "ja")).info.family, "Hiragino Sans");
+}
+
 #[test]
 fn extra_font_dirs_come_from_a_path_list() {
     assert!(extra_dirs(None).is_empty());
@@ -93,24 +143,47 @@ fn bundled_families_and_resolution() {
     assert!(!b.synth_bold);
     let faces = all_faces();
     assert!(faces.iter().any(|f| f.info.family == "Noto Serif" && f.info.style == "Regular" && f.info.origin == "bundled"));
-    // A real installed Bold Italic takes priority. Partial installed families can instead
-    // supply the nearest weight/slant, so neither synthesis flag is fixed by the OS.
+    // A real installed Bold Italic — the face's own style, or a named instance of a variable
+    // face — takes priority. Partial installed families can instead supply the nearest
+    // weight/slant, so neither synthesis flag is fixed by the OS.
     for family in ["Noto Serif", "Inter"] {
         let resolved = resolve(family, "Bold Italic");
         let selected = face(resolved.face);
         assert!(selected.info.family.eq_ignore_ascii_case(family));
         assert!(!resolved.missing);
         let candidates: Vec<_> = faces.iter().filter(|f| f.info.family.eq_ignore_ascii_case(family)).collect();
-        if let Some(exact) = candidates.iter().find(|f| f.info.style.eq_ignore_ascii_case("Bold Italic")) {
+        let exact = candidates
+            .iter()
+            .find(|f| f.info.style.eq_ignore_ascii_case("Bold Italic"))
+            .or_else(|| candidates.iter().find(|f| f.info.instances.iter().any(|i| i.style.eq_ignore_ascii_case("Bold Italic"))));
+        if let Some(exact) = exact {
             assert_eq!(resolved.face, exact.id, "real style wins for {family}");
+            let expected_instance = if exact.info.style.eq_ignore_ascii_case("Bold Italic") {
+                None
+            } else {
+                exact.info.instances.iter().position(|i| i.style.eq_ignore_ascii_case("Bold Italic")).and_then(|i| u16::try_from(i).ok())
+            };
+            assert_eq!(resolved.instance, expected_instance, "exact style instance for {family}");
             assert!(!resolved.synth_bold && !resolved.synth_italic);
         } else {
-            // Italic mismatch dominates any supported font weight distance.
-            let distance = |f: &Face| u32::from(f.info.weight.abs_diff(700)) + if f.info.italic { 0 } else { 1_000 };
-            let nearest = candidates.iter().map(|f| distance(f)).min().unwrap();
-            assert_eq!(distance(&selected), nearest, "closest available style for {family}");
-            assert_eq!(resolved.synth_bold, selected.info.weight <= 500);
-            assert_eq!(resolved.synth_italic, !selected.info.italic);
+            // Italic mismatch dominates any supported font weight distance. Named instances
+            // resolve at their effective weight and slant, not the face's defaults.
+            let selected_instance = resolved.instance.and_then(|i| selected.info.instances.get(usize::from(i)));
+            let selected_weight = selected_instance.map_or(selected.info.weight, |i| i.weight(selected.info.weight));
+            let selected_italic = selected_instance.map_or(selected.info.italic, |i| i.italic(selected.info.italic));
+            let distance = |weight: u16, italic: bool| u32::from(weight.abs_diff(700)) + if italic { 0 } else { 1_000 };
+            let nearest = candidates
+                .iter()
+                .flat_map(|f| {
+                    std::iter::once((f.info.weight, f.info.italic))
+                        .chain(f.info.instances.iter().map(move |i| (i.weight(f.info.weight), i.italic(f.info.italic))))
+                })
+                .map(|(weight, italic)| distance(weight, italic))
+                .min()
+                .unwrap();
+            assert_eq!(distance(selected_weight, selected_italic), nearest, "closest available style for {family}");
+            assert_eq!(resolved.synth_bold, selected_weight <= 500);
+            assert_eq!(resolved.synth_italic, !selected_italic);
         }
     }
 }
@@ -164,6 +237,7 @@ fn variable_named_instances_resolve_and_list() {
         ("Regular", 400.0, Some("EffectCraftInstanceTest-Regular")),
         ("Black", 900.0, Some("EffectCraftInstanceTest-Black")),
         ("Extra Bold", 800.0, None),
+        ("Bold Italic", 700.0, Some("EffectCraftInstanceTest-BoldItalic")),
     ];
     assert_eq!(add_font_data(crate::sfnt::test_font::variable(FAMILY, &instances, true)).len(), 1);
     let wght = |r: &Resolved| instance_variations(r);
@@ -185,10 +259,15 @@ fn variable_named_instances_resolve_and_list() {
     assert_eq!(wght(&ps), vec![("wght".to_string(), 900.0)]);
     assert_eq!(wght(&resolve("EffectCraftInstanceTest-ExtraBold", "")), vec![("wght".to_string(), 800.0)]);
     assert_eq!(wght(&resolve("effectcraft instance test extra bold", "")), vec![("wght".to_string(), 800.0)]);
+    // A named instance keeps its own index, so layout applies its axis values.
+    let bold_italic = resolve(FAMILY, "Bold Italic");
+    assert!(!bold_italic.missing && !bold_italic.synth_bold && !bold_italic.synth_italic);
+    assert_eq!((bold_italic.face, bold_italic.instance), (black.face, Some(4)));
+    assert_eq!(wght(&bold_italic), vec![("wght".to_string(), 700.0)]);
     // The font menu lists every instance, in weight order.
     let fams = families();
     let styles = &fams.iter().find(|(f, _)| f == FAMILY).unwrap().1;
-    assert_eq!(styles, &["Light", "Regular", "Extra Bold", "Black"]);
+    assert_eq!(styles, &["Light", "Regular", "Extra Bold", "Black", "Bold Italic"]);
     // Static fonts are untouched.
     assert_eq!(resolve("Inter", "Bold").instance, None);
 }
diff --git a/crates/text/src/layout.rs b/crates/text/src/layout.rs
index 179478517..4c0b5a436 100644
--- a/crates/text/src/layout.rs
+++ b/crates/text/src/layout.rs
@@ -565,6 +565,34 @@ fn space_item(glyphs: &mut [ShapedGlyph], style: &TextStyle, text: &str, para_st
     }
 }
 
+/// After Effects' first-baseline offset of paragraph (box) text for a face at nominal size
+/// `px`: the height of its lowercase `d`, in whole thousandths of an em. Measured in After
+/// Effects 2026 (case 818): the first baseline sits 69.50 px below the box top for Times New
+/// Roman at 100 px (its `d` is 1422/2048 em, 694.3 thousandths, rounded 695) and 71.60 px for
+/// Arial (1466/2048, 715.8, rounded 716), at 50 px half of that; superscript text keeps the
+/// line where normal text puts it and only raises its glyphs. `None` without a `d` outline.
+fn first_ascent(face: FaceId, px: f32) -> Option<f32> {
+    let f = fonts::face(face);
+    let gid = f.glyph('d')?;
+    let units = crate::outline_units(face, gid)?;
+    let top = kurbo::Shape::bounding_box(&*units).y1 as f32;
+    let em = (top / f.units_per_em() * 1000.0).round() / 1000.0;
+    plausible_first(em, px, f.metrics(px).ascent)
+}
+
+/// A `d` at least this fraction of the font ascent is a Latin lowercase ascender; a shorter one
+/// (a symbol or icon font's `d`) would put the first baseline almost at the box top, so the font
+/// ascent is used instead (the rule before the `d` height).
+const MIN_D_OF_ASCENT: f32 = 0.3;
+
+/// The first baseline `em * px` below the box top, if `em` (the `d` height in em) is plausible:
+/// finite, positive, under 4 em and at least [`MIN_D_OF_ASCENT`] of the font `ascent` (px).
+fn plausible_first(em: f32, px: f32, ascent: f32) -> Option<f32> {
+    let h = em * px;
+    let tall_enough = !(ascent.is_finite() && ascent > 0.0) || h >= MIN_D_OF_ASCENT * ascent;
+    (h.is_finite() && h > 0.0 && em < 4.0 && tall_enough).then_some(h)
+}
+
 struct ParaLine {
     range: Range<usize>,
     glyphs: Vec<Glyph>,
@@ -575,6 +603,9 @@ struct ParaLine {
     hang: (f32, f32),
     ascent: f32,
     descent: f32,
+    /// Where a box's first line puts its baseline below the box top ([`first_ascent`] of the
+    /// line's styles at their nominal size; the font ascent where a face has no `d`).
+    first: f32,
     /// Line advance (largest leading on the line).
     advance: f32,
     align: Align,
@@ -598,20 +629,25 @@ fn run_at(runs: &[(Range<usize>, TextStyle)], b: usize) -> usize {
 
 /// Lay out one paragraph (no newlines) whose text starts at byte `base` of the whole string.
 /// Margins (left, right) of a paragraph's first or later lines.
-fn margins_for(para: &ParagraphStyle, first: bool) -> (f32, f32) {
+/// `rtl` is the resolved paragraph direction (an unset direction follows the text).
+fn margins_for(para: &ParagraphStyle, rtl: bool, first: bool) -> (f32, f32) {
     let fi = if first { para.indent_first } else { 0.0 };
-    if para.rtl == Some(true) { (para.indent_end, para.indent_start + fi) } else { (para.indent_start + fi, para.indent_end) }
+    if rtl { (para.indent_end, para.indent_start + fi) } else { (para.indent_start + fi, para.indent_end) }
 }
 
 /// The width a line may fill (`None` for point text).
-fn avail_for(para: &ParagraphStyle, width: Option<f32>, first: bool) -> Option<f32> {
-    let (l, r) = margins_for(para, first);
+fn avail_for(para: &ParagraphStyle, rtl: bool, width: Option<f32>, first: bool) -> Option<f32> {
+    let (l, r) = margins_for(para, rtl, first);
     width.map(|w| (w - l - r).max(1.0))
 }
 
 /// The alignment of a line, justified lines that cannot stretch falling back to `justify_last`.
-fn align_for(para: &ParagraphStyle, width: Option<f32>, last: bool) -> Align {
-    if (last || width.is_none()) && para.align == Align::Justify {
+fn align_for(para: &ParagraphStyle, rtl: bool, width: Option<f32>, last: bool) -> Align {
+    if rtl && width.is_none() && para.align == Align::Justify {
+        // Right-to-left point text with a justified paragraph sits flush at its start, the
+        // right (After Effects 2026, every justify code; left-to-right not measured).
+        Align::Right
+    } else if (last || width.is_none()) && para.align == Align::Justify {
         if width.is_none() && para.justify_last == Align::Justify { Align::Left } else { para.justify_last }
     } else {
         para.align
@@ -622,6 +658,12 @@ fn style_metrics(primaries: &[Resolved], runs: &[(Range<usize>, TextStyle)], si:
     fonts::face(primaries[si].face).metrics(runs[si].1.glyph_size())
 }
 
+/// The baseline of a box's first line for style run `si`: the `d` height, else the font ascent.
+fn style_first(primaries: &[Resolved], runs: &[(Range<usize>, TextStyle)], si: usize) -> f32 {
+    let st = &runs[si].1;
+    first_ascent(primaries[si].face, st.size).unwrap_or_else(|| fonts::face(primaries[si].face).metrics(st.size).ascent)
+}
+
 /// A char's shaping inputs: (byte, char, shaped char, face, rtl, form, run).
 type CharInfo = (usize, char, char, FaceId, bool, Form, usize);
 
@@ -719,7 +761,7 @@ impl<'a> Para<'a> {
     }
 
     fn line_avail(&self, line: usize) -> f32 {
-        avail_for(self.para, self.width, line == 0).unwrap_or(f32::MAX)
+        avail_for(self.para, self.base_rtl, self.width, line == 0).unwrap_or(f32::MAX)
     }
 
     /// The byte ranges of the lines, for the wrap width.
@@ -736,8 +778,11 @@ impl<'a> Para<'a> {
         ranges
     }
 
-    /// Minimises the summed squared slack of every line but the last.
+    /// Minimises the summed squared slack of every line but the last; with Justify All the last
+    /// line is stretched too, so its slack counts (After Effects then balances the lines: 4 / 4 / 4
+    /// words where the other modes break 6 / 6 / 1).
     fn optimal_breaks(&self, opps: &[usize]) -> Vec<Range<usize>> {
+        let last_counts = self.para.align == Align::Justify && self.para.justify_last == Align::Justify;
         let nodes: Vec<usize> = std::iter::once(0).chain(opps.iter().copied()).collect();
         let m = nodes.len();
         let mut best = vec![(f32::INFINITY, 0usize); m];
@@ -757,7 +802,7 @@ impl<'a> Para<'a> {
                 let slack = maxw - w;
                 let cost = if over {
                     1e12 + w
-                } else if j == m - 1 {
+                } else if j == m - 1 && !last_counts {
                     0.0
                 } else {
                     slack * slack
@@ -802,8 +847,8 @@ impl<'a> Para<'a> {
 
     /// The line over byte range `r`: the `li`-th of the paragraph, `last` if it is the final one.
     fn place_line(&self, li: usize, r: Range<usize>, last: bool) -> ParaLine {
-        let align = align_for(self.para, self.width, last);
-        let avail = avail_for(self.para, self.width, li == 0);
+        let align = align_for(self.para, self.base_rtl, self.width, last);
+        let avail = avail_for(self.para, self.base_rtl, self.width, li == 0);
         let (ce, tw) = self.trailing_ws(&r);
         let hang = self.hang_of(&r, ce);
         let content = self.range_w(r.start..ce);
@@ -819,7 +864,7 @@ impl<'a> Para<'a> {
         }
         let placed = self.place_glyphs(&r, space_extra, ce);
         let carets = self.carets(&r, &placed.extents, placed.pen);
-        let (asc, desc, adv) = self.line_metrics(&r, &placed.glyphs);
+        let (asc, desc, adv, first) = self.line_metrics(&r, &placed.glyphs);
         let content_w = if space_extra > 0.0 { avail.map_or(content, |a| a + hang.0 + hang.1) } else { content };
         ParaLine {
             range: self.base + r.start..self.base + r.end,
@@ -830,10 +875,11 @@ impl<'a> Para<'a> {
             hang,
             ascent: asc,
             descent: desc,
+            first,
             advance: adv,
             align,
             avail,
-            margins: margins_for(self.para, li == 0),
+            margins: margins_for(self.para, self.base_rtl, li == 0),
             underline: placed.underline,
         }
     }
@@ -938,8 +984,8 @@ impl<'a> Para<'a> {
     }
 
     /// Ascent, descent and advance of the line: the tallest face and the largest leading on it.
-    fn line_metrics(&self, r: &Range<usize>, glyphs: &[Glyph]) -> (f32, f32, f32) {
-        let (mut asc, mut desc, mut adv) = (0.0f32, 0.0f32, 0.0f32);
+    fn line_metrics(&self, r: &Range<usize>, glyphs: &[Glyph]) -> (f32, f32, f32, f32) {
+        let (mut asc, mut desc, mut adv, mut first) = (0.0f32, 0.0f32, 0.0f32, 0.0f32);
         let char_start = self.chars.partition_point(|c| c.0 < r.start);
         let char_end = self.chars.partition_point(|c| c.0 < r.end);
         let mut seen: Vec<usize> = self.chars[char_start..char_end].iter().map(|c| c.6).collect();
@@ -954,6 +1000,7 @@ impl<'a> Para<'a> {
             asc = asc.max(m.ascent + rise.max(0.0));
             desc = desc.max(m.descent - rise.min(0.0));
             adv = adv.max(self.runs[si].1.line_advance());
+            first = first.max(style_first(self.primaries, self.runs, si));
         }
         for g in glyphs {
             if g.face != self.primaries[g.run].face {
@@ -962,7 +1009,7 @@ impl<'a> Para<'a> {
                 desc = desc.max(m.descent);
             }
         }
-        (asc, desc, adv)
+        (asc, desc, adv, first)
     }
 }
 
@@ -1037,6 +1084,8 @@ fn paragraph(
     if text.is_empty() {
         let si = run_at(runs, base);
         let pm = style_metrics(primaries, runs, si);
+        // No text to resolve a direction from: the explicit one.
+        let rtl = para.rtl == Some(true);
         return vec![ParaLine {
             range: base..base,
             glyphs: vec![],
@@ -1047,9 +1096,10 @@ fn paragraph(
             ascent: pm.ascent,
             descent: pm.descent,
             advance: runs[si].1.line_advance(),
-            align: align_for(para, width, true),
-            avail: avail_for(para, width, true),
-            margins: margins_for(para, true),
+            first: style_first(primaries, runs, si),
+            align: align_for(para, rtl, width, true),
+            avail: avail_for(para, rtl, width, true),
+            margins: margins_for(para, rtl, true),
             underline: None,
         }];
     }
@@ -1120,7 +1170,10 @@ pub fn layout_rich_uncached(text: &str, runs: &[(Range<usize>, TextStyle)], para
     for (i, (pi, pl)) in plines.into_iter().enumerate() {
         let para = para_at(pi);
         if i == 0 {
-            baseline = if width.is_some() { pl.ascent } else { 0.0 };
+            // Vertical type keeps its first column at the font ascent (not measured in AE).
+            let vertical = runs.get(run_at(runs, pl.range.start)).is_some_and(|r| r.1.vertical)
+                || runs.iter().any(|r| r.1.vertical && r.0.start < pl.range.end && r.0.end > pl.range.start);
+            baseline = if width.is_some() { if vertical { pl.ascent } else { pl.first } } else { 0.0 };
         } else {
             let prev_para = lay.lines.last().map_or(pi, |l| l.para);
             let mut adv = pl.advance + para.leading;
diff --git a/crates/text/src/layout/tests.rs b/crates/text/src/layout/tests.rs
index 9079a1225..5792c1c16 100644
--- a/crates/text/src/layout/tests.rs
+++ b/crates/text/src/layout/tests.rs
@@ -357,3 +357,140 @@ fn named_instance_sets_the_base_variations() {
     let inter = layout_uncached("Hi", &TextStyle::default(), &ParagraphStyle::default());
     assert!(inter.glyphs.iter().all(|g| g.variations == 0));
 }
+
+/// After Effects 2026 (case 818): box text's first baseline is the `d` height (in whole
+/// thousandths of an em) below the box top, at the nominal size also for superscript, whose
+/// glyphs are then raised. EffectCraft used the font ascent of the drawn size (plus the
+/// superscript rise): 89.1 px instead of 69.5 for Times New Roman at 100 px, and the
+/// superscript glyphs 15.8 px low.
+#[test]
+fn box_text_first_baseline_is_the_d_height_as_after_effects() {
+    let boxed = ParagraphStyle { width: Some(600.0), ..Default::default() };
+    // The rule on a bundled face (works everywhere).
+    for (family, size) in [("Inter", 100.0f32), ("Noto Serif", 50.0)] {
+        let s = TextStyle { family: family.into(), ..st(size) };
+        let r = fonts::resolve(family, "Regular");
+        let f = fonts::face(r.face);
+        let d = crate::outline_units(r.face, f.glyph('d').unwrap()).unwrap();
+        let em = (kurbo::Shape::bounding_box(&*d).y1 as f32 / f.units_per_em() * 1000.0).round() / 1000.0;
+        let l = layout("Hxg", &s, &boxed);
+        assert!((l.lines[0].baseline - em * size).abs() < 1e-3, "{family}: {} vs {}", l.lines[0].baseline, em * size);
+        assert!(l.lines[0].baseline < l.lines[0].ascent, "{family}: below the full ascent");
+    }
+    // After Effects' numbers, where the real fonts are installed.
+    for (family, ae_normal) in [("Times New Roman", 69.5008f32), ("Arial", 71.5988)] {
+        let r = fonts::resolve(family, "Regular");
+        if fonts::face(r.face).info.family != family {
+            continue;
+        }
+        for (size, script, glyph_baseline) in
+            [(100.0, Script::Normal, ae_normal), (50.0, Script::Normal, ae_normal / 2.0), (100.0, Script::Super, ae_normal - 100.0 * SCRIPT_OFFSET)]
+        {
+            let s = TextStyle { family: family.into(), script, ..st(size) };
+            let l = layout("Hxg", &s, &boxed);
+            let drawn = l.glyphs[0].y;
+            assert!((drawn - glyph_baseline).abs() < 0.15, "{family} {size} {script:?}: {drawn} vs AE {glyph_baseline}");
+        }
+    }
+}
+
+/// CodeRabbit on #1875: a face whose `d` is very short (a symbol or icon font) would put the
+/// first baseline almost at the box top; below 0.3 of the ascent the font ascent is used.
+#[test]
+fn a_short_d_falls_back_to_the_font_ascent() {
+    // Latin faces: the `d` is about 0.7 em, the ascent about 0.9 em.
+    let near = |v: Option<f32>, want: f32| v.is_some_and(|v| (v - want).abs() < 1e-3);
+    assert!(near(plausible_first(0.7, 100.0, 90.0), 70.0));
+    // A `d` a tenth of the ascent: not a lowercase ascender.
+    assert_eq!(plausible_first(0.09, 100.0, 90.0), None);
+    assert_eq!(plausible_first(0.26, 100.0, 90.0), None);
+    assert!(near(plausible_first(0.28, 100.0, 90.0), 28.0));
+    // Broken values stay rejected; an unusable ascent does not reject a sane `d`.
+    for (em, px) in [(0.0, 100.0), (-0.5, 100.0), (f32::NAN, 100.0), (5.0, 100.0), (0.7, f32::INFINITY)] {
+        assert_eq!(plausible_first(em, px, 90.0), None, "{em} {px}");
+    }
+    assert!(near(plausible_first(0.7, 100.0, f32::NAN), 70.0));
+    // The bundled faces keep the `d` rule.
+    for family in ["Inter", "Noto Serif"] {
+        let r = fonts::resolve(family, "Regular");
+        assert!(first_ascent(r.face, 100.0).is_some(), "{family}");
+    }
+}
+
+/// After Effects 2026 (EXPORTER t6): with Justify All and the every-line composer, a box that
+/// the other justifications break into lines of 6, 6 and 1 words breaks 4 / 4 / 4, so the
+/// stretched last line is not a lone word; word positions then match AE to 1 px.
+#[test]
+fn justify_all_balances_the_lines_with_the_every_line_composer() {
+    let text = "one two three four five six seven eight nine ten eleven twelve";
+    let s = st(30.0);
+    let words = |l: &Layout| -> Vec<usize> { l.lines.iter().map(|ln| text[ln.range.clone()].split_whitespace().count()).collect() };
+    let p = |last: Align| ParagraphStyle { width: Some(450.0), align: Align::Justify, justify_last: last, every_line: true, ..Default::default() };
+    let left = layout_rich_uncached(text, &[(0..text.len(), s.clone())], &[p(Align::Left)]);
+    let all = layout_rich_uncached(text, &[(0..text.len(), s)], &[p(Align::Justify)]);
+    let (wl, wa) = (words(&left), words(&all));
+    assert!(wl.last().copied().unwrap_or(0) < *wl.first().unwrap_or(&0), "{wl:?}");
+    let (lo, hi) = (wa.iter().min().copied().unwrap_or(0), wa.iter().max().copied().unwrap_or(0));
+    assert!(hi - lo <= 1, "Justify All balances the lines: {wa:?} (left-justified: {wl:?})");
+}
+
+/// After Effects 2026 (EXPORTER read-back t7): right-to-left point text with any justified
+/// code (justify last left / centre / right, justify all) sits flush right at its anchor, as
+/// right-aligned text does.
+#[test]
+fn rtl_point_text_with_a_justified_paragraph_is_flush_at_its_start() {
+    let text = "Right to left";
+    let s = st(30.0);
+    let at = |align: Align, last: Align| {
+        let p = ParagraphStyle { align, justify_last: last, rtl: Some(true), ..Default::default() };
+        let l = layout_rich_uncached(text, &[(0..text.len(), s.clone())], &[p]);
+        (l.lines[0].x, l.lines[0].x + l.lines[0].width)
+    };
+    let right = at(Align::Right, Align::Left);
+    for last in [Align::Left, Align::Center, Align::Right, Align::Justify] {
+        let got = at(Align::Justify, last);
+        assert!((got.0 - right.0).abs() < 1e-3 && (got.1 - right.1).abs() < 1e-3, "{last:?}: {got:?} vs right-aligned {right:?}");
+    }
+}
+
+/// The same holds when the direction is unset and the text itself resolves right to left.
+#[test]
+fn detected_rtl_point_text_with_a_justified_paragraph_is_flush_at_its_start() {
+    let text = "\u{5d0}\u{5d1}\u{5d2} \u{5d3}\u{5d4}";
+    let s = st(30.0);
+    let at = |align: Align| {
+        let p = ParagraphStyle { align, justify_last: Align::Left, rtl: None, ..Default::default() };
+        let l = layout_rich_uncached(text, &[(0..text.len(), s.clone())], &[p]);
+        (l.lines[0].x, l.lines[0].x + l.lines[0].width)
+    };
+    let (right, got) = (at(Align::Right), at(Align::Justify));
+    assert!((got.0 - right.0).abs() < 1e-3 && (got.1 - right.1).abs() < 1e-3, "{got:?} vs right-aligned {right:?}");
+}
+
+/// Indents follow the resolved direction too: detected right-to-left text puts its start
+/// indent on the right, as an explicit right-to-left paragraph does.
+#[test]
+fn detected_rtl_text_takes_its_indents_on_the_rtl_sides() {
+    let text = "\u{5d0}\u{5d1}\u{5d2} \u{5d3}\u{5d4}";
+    let s = st(30.0);
+    let at = |rtl: Option<bool>| {
+        let p = ParagraphStyle { align: Align::Justify, justify_last: Align::Left, indent_start: 20.0, rtl, ..Default::default() };
+        let l = layout_rich_uncached(text, &[(0..text.len(), s.clone())], &[p]);
+        (l.lines[0].x, l.lines[0].x + l.lines[0].width)
+    };
+    let (explicit, detected) = (at(Some(true)), at(None));
+    assert!((detected.0 - explicit.0).abs() < 1e-3 && (detected.1 - explicit.1).abs() < 1e-3, "{detected:?} vs {explicit:?}");
+}
+
+/// Only the first line's own runs decide whether box text starts at the font ascent: a
+/// vertical run further down leaves a horizontal first line on its `d`-height baseline.
+#[test]
+fn a_later_vertical_run_keeps_the_first_line_baseline() {
+    let text = "Top\nside";
+    let horiz = st(40.0);
+    let vert = TextStyle { vertical: true, ..horiz.clone() };
+    let p = ParagraphStyle { width: Some(400.0), ..Default::default() };
+    let plain = layout_rich_uncached(text, &[(0..text.len(), horiz.clone())], std::slice::from_ref(&p));
+    let mixed = layout_rich_uncached(text, &[(0..4, horiz), (4..text.len(), vert)], &[p]);
+    assert!((mixed.lines[0].baseline - plain.lines[0].baseline).abs() < 1e-3, "{} vs {}", mixed.lines[0].baseline, plain.lines[0].baseline);
+}
diff --git a/crates/text/src/lib.rs b/crates/text/src/lib.rs
index 35e7ecc06..8cc8e3264 100644
--- a/crates/text/src/lib.rs
+++ b/crates/text/src/lib.rs
@@ -659,7 +659,9 @@ mod tests {
         let doc = TextDoc { text: "ab cd".into(), size: 20.0, box_size: Some([200.0, 100.0]), box_pos: [-100.0, -50.0], ..Default::default() };
         let l = layout_doc(&doc);
         let (a, _) = l.caret(0);
-        assert!((a.x + 100.0).abs() < 1e-6 && (a.y + 50.0).abs() < 1.0, "{a:?}");
+        // The first baseline sits the `d` height below the box top (After Effects), so the
+        // caret, which spans the font's full ascent, starts a little above the box.
+        assert!((a.x + 100.0).abs() < 1e-6 && a.y + 50.0 < 0.0 && a.y + 50.0 > -0.35 * 20.0, "{a:?}");
         // Vertical: characters run down a column, carets are horizontal.
         let v = layout_doc(&TextDoc { text: "abc\nde".into(), size: 20.0, vertical: true, ..Default::default() });
         let ys: Vec<f64> = v.glyphs.iter().filter(|g| g.line_index == 0).map(|g| g.origin.y).collect();
diff --git a/crates/text/src/selectors.rs b/crates/text/src/selectors.rs
index e3a422460..fcecfd814 100644
--- a/crates/text/src/selectors.rs
+++ b/crates/text/src/selectors.rs
@@ -71,6 +71,15 @@ impl Mode {
     pub fn combine(self, acc: f64, v: f64) -> f64 {
         let r = match self {
             Mode::Add => acc + v,
+            // Subtracting more than is selected leaves nothing, not a negative selection (After
+            // Effects 2026: a Subtract selector over unselected characters leaves their
+            // Tracking at 0, EXPORTER read-back t8).
+            // Intended for every animator property, not only Tracking: selectors combine into one
+            // selection per character for the whole animator (`render::text::animator_selection`),
+            // which then scales each of its properties, as in After Effects, where selectors
+            // belong to the animator. The read-back observed that selection through Tracking;
+            // Opacity, Position and the rest were not measured separately.
+            Mode::Subtract if acc >= 0.0 => (acc - v).max(0.0),
             Mode::Subtract => acc - v,
             Mode::Intersect => acc * v,
             Mode::Min => acc.min(v),
@@ -352,6 +361,9 @@ mod tests {
         // A lone Subtract inverts.
         assert_eq!(Mode::Subtract.combine(Mode::Subtract.initial(), 1.0), 0.0);
         assert_eq!(Mode::Subtract.combine(Mode::Subtract.initial(), 0.0), 1.0);
+        // Subtracting from what is not selected leaves 0, not a negative selection (AE t8).
+        assert_eq!(Mode::Subtract.combine(0.0, 1.0), 0.0);
+        assert_eq!(Mode::Subtract.combine(0.25, 1.0), 0.0);
         assert_eq!(Mode::from_index(5), Mode::Difference);
     }
 
diff --git a/crates/track/src/camtrack/bundle.rs b/crates/track/src/camtrack/bundle.rs
index b8421f144..a4412dbce 100644
--- a/crates/track/src/camtrack/bundle.rs
+++ b/crates/track/src/camtrack/bundle.rs
@@ -11,7 +11,7 @@
 use rayon::prelude::*;
 
 use super::geometry::Pose;
-use super::linalg::{M3, V3, add, cholesky_solve, dot, inv3, mm, mtv, mv, rodrigues, scale, skew, sub};
+use super::linalg::{M3, V3, add, cholesky_solve, conjugate_gradient, dot, inv3, mm, mtv, mv, rodrigues, scale, skew, sub};
 use super::{Distortion, SolveError};
 
 /// A camera in the adjustment.
@@ -287,6 +287,101 @@ fn cam_jac(l: &Layout, ci: usize, c: &BaCam, xc: V3, a: &[[f64; 3]; 2], p: [f64;
     }
 }
 
+struct PtSys {
+    v: M3,
+    bp: V3,
+    w: Vec<(usize, V3)>,
+}
+
+struct PreconditionerBlock {
+    start: usize,
+    dim: usize,
+    inverse: Vec<f64>,
+}
+
+fn camera_preconditioner(u: &[f64], l: &Layout) -> Option<Vec<PreconditionerBlock>> {
+    let mut ranges = Vec::new();
+    let pose_dim = if l.rot_only { 3 } else { 6 };
+    for (&pose, &focal) in l.start.iter().zip(&l.fidx) {
+        if pose != usize::MAX {
+            ranges.push((pose, pose_dim + usize::from(focal != usize::MAX)));
+        } else if focal != usize::MAX {
+            ranges.push((focal, 1));
+        }
+    }
+    if let Some(start) = l.shared.or(l.dist) {
+        ranges.push((start, l.n - start));
+    }
+    ranges
+        .into_iter()
+        .map(|(start, dim)| {
+            let mut matrix = Vec::with_capacity(dim * dim);
+            for i in 0..dim {
+                for j in 0..dim {
+                    matrix.push(*u.get((start + i) * l.n + start + j)?);
+                }
+            }
+            let mut inverse = vec![0.0; dim * dim];
+            for col in 0..dim {
+                let mut a = matrix.clone();
+                let mut b = vec![0.0; dim];
+                *b.get_mut(col)? = 1.0;
+                if !cholesky_solve(&mut a, dim, &mut b) {
+                    return None;
+                }
+                for (row, value) in b.into_iter().enumerate() {
+                    inverse[row * dim + col] = value;
+                }
+            }
+            Some(PreconditionerBlock { start, dim, inverse })
+        })
+        .collect()
+}
+
+/// Apply the point-eliminated system without materialising W V^-1 W^T.
+fn iterative_schur(u: &[f64], rhs: &[f64], systems: &[PtSys], vinv: &[Option<M3>], l: &Layout) -> Option<Vec<f64>> {
+    if l.n == 0 || l.n.checked_mul(l.n) != Some(u.len()) || rhs.len() != l.n || systems.len() != vinv.len() {
+        return None;
+    }
+    let blocks = camera_preconditioner(u, l)?;
+    // U contains camera blocks, global parameters and the focal prior. Store its nonzeros
+    // once; all subsequent products are linear in these and the point-camera connections.
+    let rows: Vec<Vec<(usize, f64)>> =
+        u.chunks_exact(l.n).map(|row| row.iter().enumerate().filter(|(_, v)| **v != 0.0).map(|(i, v)| (i, *v)).collect()).collect();
+    let mut reduced_rhs = rhs.to_vec();
+    for (ps, vi) in systems.iter().zip(vinv) {
+        let Some(vi) = vi else { continue };
+        let vb = mv(vi, ps.bp);
+        for (i, w) in &ps.w {
+            *reduced_rhs.get_mut(*i)? -= dot(*w, vb);
+        }
+    }
+    conjugate_gradient(
+        &reduced_rhs,
+        |x, y| {
+            for (i, row) in rows.iter().enumerate() {
+                y[i] = row.iter().map(|(j, v)| v * x[*j]).sum();
+            }
+            for (ps, vi) in systems.iter().zip(vinv) {
+                let Some(vi) = vi else { continue };
+                let q = ps.w.iter().fold([0.0; 3], |q, (i, w)| add(q, scale(*w, x[*i])));
+                let q = mv(vi, q);
+                for (i, w) in &ps.w {
+                    y[*i] -= dot(*w, q);
+                }
+            }
+        },
+        |r, z| {
+            z.fill(0.0);
+            for block in &blocks {
+                for i in 0..block.dim {
+                    z[block.start + i] = (0..block.dim).map(|j| block.inverse[i * block.dim + j] * r[block.start + j]).sum();
+                }
+            }
+        },
+    )
+}
+
 /// Smooth per-camera log focal lengths in the normal equations.
 fn add_focal_prior(cams: &[BaCam], o: &BaOpts, l: &Layout, s_mat: &mut [f64], bc: &mut [f64]) {
     let n = l.n;
@@ -310,10 +405,56 @@ fn add_focal_prior(cams: &[BaCam], o: &BaOpts, l: &Layout, s_mat: &mut [f64], bc
     }
 }
 
+/// Eliminate the points into the camera system explicitly (`S -= W V^-1 W^T`, `rhs -= W V^-1 bp`).
+fn reduce_points(systems: &[PtSys], vinv: &[Option<M3>], n: usize, s: &mut [f64], rhs: &mut [f64]) {
+    let npts = systems.len();
+    let reduce = |range: std::ops::Range<usize>, s: &mut [f64], rhs: &mut [f64]| {
+        for j in range {
+            let (Some(vi), ps) = (&vinv[j], &systems[j]) else { continue };
+            let vb = mv(vi, ps.bp);
+            let wv: Vec<V3> = ps.w.iter().map(|(_, w)| mv(vi, *w)).collect();
+            for (a, (ia, wa)) in ps.w.iter().enumerate() {
+                rhs[*ia] -= dot(*wa, vb);
+                for (ib, wb) in &ps.w[a..] {
+                    let d = dot(wv[a], *wb);
+                    s[ia * n + ib] -= d;
+                    if ia != ib {
+                        s[ib * n + ia] -= d;
+                    }
+                }
+            }
+        }
+    };
+    let chunks = rayon::current_num_threads().clamp(1, 8);
+    if n <= 1200 && npts >= 64 && chunks > 1 {
+        let per = npts.div_ceil(chunks);
+        let parts: Vec<(Vec<f64>, Vec<f64>)> = (0..chunks)
+            .into_par_iter()
+            .map(|t| {
+                let (mut ds, mut dr) = (vec![0.0; n * n], vec![0.0; n]);
+                reduce(t * per..((t + 1) * per).min(npts), &mut ds, &mut dr);
+                (ds, dr)
+            })
+            .collect();
+        for (ds, dr) in parts {
+            s.par_iter_mut().zip(ds.par_iter()).for_each(|(x, y)| *x += y);
+            for (x, y) in rhs.iter_mut().zip(dr) {
+                *x += y;
+            }
+        }
+    } else {
+        reduce(0..npts, s, rhs);
+    }
+}
+
 /// Run Levenberg–Marquardt. `cams` and `pts` are updated in place.
 /// Invalid inputs or workspaces exceeding 256 MiB return an error before mutation.
 pub fn adjust(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts) -> Result<BaReport, SolveError> {
     validate(cams, pts, obs, o)?;
+    adjust_impl(cams, pts, obs, o, true)
+}
+
+fn adjust_impl(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts, allow_iterative: bool) -> Result<BaReport, SolveError> {
     let l = layout(cams.len(), o);
     let matrix_len = matrix_len(l.n, pts.len(), obs.len())?;
     let npts = pts.len();
@@ -341,11 +482,6 @@ pub fn adjust(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts) ->
         iters += 1;
         // ---- Normal equations (Gauss–Newton with IRLS weights).
         // Per point: V (3×3), bp (3), W entries (cam-side index → 3).
-        struct PtSys {
-            v: [[f64; 3]; 3],
-            bp: V3,
-            w: Vec<(usize, V3)>,
-        }
         let build_point = |j: usize, s_acc: &mut Vec<f64>, bc: &mut Vec<f64>| -> PtSys {
             let mut ps = PtSys { v: [[0.0; 3]; 3], bp: [0.0; 3], w: vec![] };
             let mut jc = CameraJacobian::new();
@@ -445,6 +581,10 @@ pub fn adjust(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts) ->
         let base_s = s_mat.clone();
         let base_bc = bc.clone();
         let mean_diag = ((0..n).map(|i| base_s[i * n + i]).sum::<f64>() / n.max(1) as f64).max(1e-12);
+        let schur_pairs = systems.iter().fold(0usize, |sum, ps| sum.saturating_add(ps.w.len().saturating_mul(ps.w.len().saturating_add(1)) / 2));
+        // Reserve the iterative solve for expensive long-track reductions; small systems
+        // retain the direct path and its rounding. Failed solves use the direct path too.
+        let mut use_iterative = allow_iterative && !o.fix_points && n >= 120 && schur_pairs > 4_000_000;
         // ---- Try steps with increasing damping.
         let mut accepted = false;
         for _try in 0..12 {
@@ -472,50 +612,26 @@ pub fn adjust(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts) ->
                     })
                     .collect()
             };
-            if !o.fix_points {
-                let reduce = |range: std::ops::Range<usize>, s: &mut [f64], rhs: &mut [f64]| {
-                    for j in range {
-                        let (Some(vi), ps) = (&vinv[j], &systems[j]) else { continue };
-                        let vb = mv(vi, ps.bp);
-                        let wv: Vec<V3> = ps.w.iter().map(|(_, w)| mv(vi, *w)).collect();
-                        for (a, (ia, wa)) in ps.w.iter().enumerate() {
-                            rhs[*ia] -= dot(*wa, vb);
-                            for (ib, wb) in &ps.w[a..] {
-                                let d = dot(wv[a], *wb);
-                                s[ia * n + ib] -= d;
-                                if ia != ib {
-                                    s[ib * n + ia] -= d;
-                                }
-                            }
-                        }
-                    }
-                };
-                let chunks = rayon::current_num_threads().clamp(1, 8);
-                if n <= 1200 && npts >= 64 && chunks > 1 {
-                    let per = npts.div_ceil(chunks);
-                    let parts: Vec<(Vec<f64>, Vec<f64>)> = (0..chunks)
-                        .into_par_iter()
-                        .map(|t| {
-                            let (mut ds, mut dr) = (vec![0.0; matrix_len], vec![0.0; n]);
-                            reduce(t * per..((t + 1) * per).min(npts), &mut ds, &mut dr);
-                            (ds, dr)
-                        })
-                        .collect();
-                    for (ds, dr) in parts {
-                        s.par_iter_mut().zip(ds.par_iter()).for_each(|(x, y)| *x += y);
-                        for (x, y) in rhs.iter_mut().zip(dr) {
-                            *x += y;
-                        }
-                    }
-                } else {
-                    reduce(0..npts, &mut s, &mut rhs);
+            let iterative_step = if use_iterative { iterative_schur(&s, &rhs, &systems, &vinv, &l) } else { None };
+            if dbg && use_iterative {
+                eprintln!("ba iterative n={n} pairs={schur_pairs} solved={}", iterative_step.is_some());
+            }
+            if use_iterative && iterative_step.is_none() {
+                use_iterative = false;
+            }
+            let dc = if let Some(dc) = iterative_step {
+                dc
+            } else {
+                if !o.fix_points {
+                    reduce_points(&systems, &vinv, n, &mut s, &mut rhs);
                 }
-            }
-            let mut dc = rhs;
-            if n > 0 && !cholesky_solve(&mut s, n, &mut dc) {
-                lambda *= 10.0;
-                continue;
-            }
+                let mut dc = rhs;
+                if n > 0 && !cholesky_solve(&mut s, n, &mut dc) {
+                    lambda *= 10.0;
+                    continue;
+                }
+                dc
+            };
             // Apply.
             let mut nc: Vec<BaCam> = cams.to_vec();
             for (i, c) in nc.iter_mut().enumerate() {
@@ -593,6 +709,112 @@ pub fn adjust(cams: &mut [BaCam], pts: &mut [V3], obs: &[BaObs], o: &BaOpts) ->
 mod tests {
     use super::*;
     use crate::camtrack::geometry::Rng;
+    use crate::camtrack::linalg::{I3, log_rot, mt, norm};
+
+    #[test]
+    fn long_track_adjustment_matches_direct_reprojections_and_outliers() {
+        rayon::ThreadPoolBuilder::new().num_threads(1).build().unwrap().install(|| {
+            for (focal, fix_centers, distortion) in
+                [(FocalMode::Fixed, false, false), (FocalMode::Shared, false, true), (FocalMode::PerCamera(30.0), false, true), (FocalMode::Shared, true, true)]
+            {
+                let mut rng = Rng(71);
+                let mut noise = || (rng.next_u64() % 100_000) as f64 / 100_000.0 - 0.5;
+                let truth: Vec<V3> = (0..320).map(|_| [noise() * 8.0, noise() * 5.0, 10.0 + noise() * 5.0]).collect();
+                let true_cams: Vec<_> = (0..60)
+                    .map(|i| BaCam {
+                        pose: Pose {
+                            r: rodrigues([0.001 * i as f64, -0.003 * i as f64, 0.0]),
+                            c: if fix_centers { [0.0; 3] } else { [0.03 * i as f64, 0.01 * (i as f64).sin(), 0.0] },
+                        },
+                        f: if matches!(focal, FocalMode::PerCamera(_)) { 900.0 * (1.0 + 0.05 * (i as f64 * 0.07).sin()) } else { 900.0 },
+                        dist: if distortion { Distortion { k1: 0.015, k2: -0.005, radius: 1100.0 } } else { Distortion::NONE },
+                    })
+                    .collect();
+                let mut obs = Vec::new();
+                for (ci, c) in true_cams.iter().enumerate() {
+                    for (pi, p) in truth.iter().enumerate() {
+                        let mut uv = residual(c, *p, [0.0; 2]).unwrap();
+                        uv[0] += noise() * 0.05;
+                        uv[1] += noise() * 0.05;
+                        if (ci * truth.len() + pi).is_multiple_of(37) {
+                            uv[0] += 25.0;
+                            uv[1] -= 30.0;
+                        }
+                        obs.push(BaObs { cam: ci as u32, pt: pi as u32, uv });
+                    }
+                }
+                let mut cams = true_cams.clone();
+                for c in cams.iter_mut().skip(2) {
+                    c.pose.r = mm(&rodrigues([0.001, -0.001, 0.0005]), &c.pose.r);
+                    if !fix_centers {
+                        c.pose.c = add(c.pose.c, [0.002, -0.003, 0.001]);
+                    }
+                }
+                let mut pts: Vec<_> = truth.iter().map(|p| add(*p, [0.01, -0.01, 0.005])).collect();
+                let (mut direct_cams, mut direct_pts) = (cams.clone(), pts.clone());
+                let opts = BaOpts { focal, fix_centers, distortion, fixed: (0..60).map(|i| i < 2).collect(), max_iter: 10, ..Default::default() };
+                let report = adjust(&mut cams, &mut pts, &obs, &opts).unwrap();
+                let direct = adjust_impl(&mut direct_cams, &mut direct_pts, &obs, &opts, false).unwrap();
+                assert!((report.cost - direct.cost).abs() < 1e-5 * direct.cost.max(1.0));
+                for ob in &obs {
+                    let a = residual(&cams[ob.cam as usize], pts[ob.pt as usize], ob.uv).unwrap();
+                    let b = residual(&direct_cams[ob.cam as usize], direct_pts[ob.pt as usize], ob.uv).unwrap();
+                    assert!((a[0] - b[0]).hypot(a[1] - b[1]) < 0.001);
+                    assert_eq!(a[0].hypot(a[1]) <= 4.0, b[0].hypot(b[1]) <= 4.0);
+                }
+                for (a, b) in cams.iter().zip(direct_cams) {
+                    assert!(norm(sub(a.pose.c, b.pose.c)) < 0.001);
+                    assert!(norm(log_rot(&mm(&a.pose.r, &mt(&b.pose.r)))) < 1e-4);
+                    assert!((a.f - b.f).abs() < 1e-4 * b.f);
+                    assert!((a.dist.k1 - b.dist.k1).abs() < 1e-4 && (a.dist.k2 - b.dist.k2).abs() < 1e-4);
+                }
+            }
+        });
+    }
+
+    #[test]
+    fn matrix_free_schur_matches_explicit_system_and_rejects_bad_preconditioner() {
+        let l = layout(20, &BaOpts::default());
+        let n = l.n;
+        let mut u = vec![0.0; n * n];
+        for i in 0..n {
+            u[i * n + i] = 10.0;
+        }
+        let systems: Vec<_> = (0..80)
+            .map(|j| PtSys {
+                v: I3,
+                bp: [0.01, -0.02, 0.03],
+                w: (0..n).map(|i| (i, [((j * 13 + i * 7) % 19) as f64 * 0.001 - 0.009, (i % 7) as f64 * 0.001, (j % 11) as f64 * 0.001])).collect(),
+            })
+            .collect();
+        let vinv = vec![Some(I3); systems.len()];
+        let rhs: Vec<_> = (0..n).map(|i| (i % 7) as f64 - 3.0).collect();
+        let x = iterative_schur(&u, &rhs, &systems, &vinv, &l).unwrap();
+        let mut explicit = u.clone();
+        let mut reduced_rhs = rhs.clone();
+        for ps in &systems {
+            for (i, a) in &ps.w {
+                reduced_rhs[*i] -= dot(*a, ps.bp);
+                for (j, b) in &ps.w {
+                    explicit[i * n + j] -= dot(*a, *b);
+                }
+            }
+        }
+        let mut direct = reduced_rhs.clone();
+        let mut factor = explicit.clone();
+        assert!(cholesky_solve(&mut factor, n, &mut direct));
+        for (a, b) in x.iter().zip(direct) {
+            assert!((a - b).abs() < 1e-9);
+        }
+        let mut error2 = 0.0;
+        for (i, row) in explicit.chunks_exact(n).enumerate() {
+            let ax: f64 = row.iter().zip(&x).map(|(a, x)| a * x).sum();
+            error2 += (ax - reduced_rhs[i]).powi(2);
+        }
+        assert!(error2 < 1e-18 * reduced_rhs.iter().map(|v| v * v).sum::<f64>());
+        u[0] = -1.0;
+        assert!(iterative_schur(&u, &rhs, &systems, &vinv, &l).is_none());
+    }
 
     fn test_camera() -> BaCam {
         BaCam { pose: Pose::IDENTITY, f: 900.0, dist: Distortion::NONE }
diff --git a/crates/track/src/camtrack/linalg.rs b/crates/track/src/camtrack/linalg.rs
index 692eef34e..71e88e109 100644
--- a/crates/track/src/camtrack/linalg.rs
+++ b/crates/track/src/camtrack/linalg.rs
@@ -398,6 +398,60 @@ pub fn cholesky_solve(a: &mut [f64], n: usize, b: &mut [f64]) -> bool {
     b.iter().all(|v| v.is_finite())
 }
 
+/// Preconditioned conjugate gradients with an independently recomputed residual check.
+/// Failure to converge (or non-finite/non-positive curvature) requests the direct fallback.
+pub(crate) fn conjugate_gradient(rhs: &[f64], apply: impl Fn(&[f64], &mut [f64]), precondition: impl Fn(&[f64], &mut [f64])) -> Option<Vec<f64>> {
+    let n = rhs.len();
+    let norm2 = dot_n(rhs, rhs);
+    if !norm2.is_finite() {
+        return None;
+    }
+    if rhs.iter().all(|v| *v == 0.0) {
+        return Some(vec![0.0; n]);
+    }
+    let tolerance2 = norm2 * 1e-22;
+    if tolerance2 == 0.0 {
+        return None;
+    }
+    let mut x = vec![0.0; n];
+    let mut r = rhs.to_vec();
+    let mut z = vec![0.0; n];
+    let mut ap = vec![0.0; n];
+    precondition(&r, &mut z);
+    let mut p = z.clone();
+    let mut rz = dot_n(&r, &z);
+    for _ in 0..n.saturating_mul(2).min(512) {
+        if !rz.is_finite() || rz <= 0.0 {
+            return None;
+        }
+        apply(&p, &mut ap);
+        let curvature = dot_n(&p, &ap);
+        if !curvature.is_finite() || curvature <= 0.0 {
+            return None;
+        }
+        let alpha = rz / curvature;
+        for i in 0..n {
+            x[i] += alpha * p[i];
+            r[i] -= alpha * ap[i];
+        }
+        if dot_n(&r, &r) <= tolerance2 {
+            apply(&x, &mut ap);
+            for i in 0..n {
+                ap[i] = rhs[i] - ap[i];
+            }
+            return (x.iter().all(|v| v.is_finite()) && dot_n(&ap, &ap) <= 100.0 * tolerance2).then_some(x);
+        }
+        precondition(&r, &mut z);
+        let next_rz = dot_n(&r, &z);
+        let beta = next_rz / rz;
+        for i in 0..n {
+            p[i] = z[i] + beta * p[i];
+        }
+        rz = next_rz;
+    }
+    None
+}
+
 /// A similarity transform `x ↦ s R x + t`.
 #[derive(Clone, Copy, Debug, PartialEq, serde::Serialize, serde::Deserialize)]
 pub struct Similarity {
@@ -586,6 +640,30 @@ mod tests {
         assert!(cholesky_solve(&mut [], 0, &mut []));
     }
 
+    #[test]
+    fn conjugate_gradient_checks_residual_and_bad_curvature() {
+        let n = 64;
+        let rhs: Vec<f64> = (0..n).map(|i| (i % 11) as f64 - 5.0).collect();
+        let apply = |x: &[f64], y: &mut [f64]| {
+            for i in 0..n {
+                y[i] = 4.0 * x[i] + if i > 0 { x[i - 1] } else { 0.0 } + if i + 1 < n { x[i + 1] } else { 0.0 };
+            }
+        };
+        let x = conjugate_gradient(&rhs, apply, |r, z| {
+            for (r, z) in r.iter().zip(z) {
+                *z = *r / 4.0;
+            }
+        })
+        .unwrap();
+        let mut product = vec![0.0; n];
+        apply(&x, &mut product);
+        let residual: f64 = rhs.iter().zip(product).map(|(b, ax)| (b - ax).powi(2)).sum();
+        assert!(residual < 1e-18 * dot_n(&rhs, &rhs));
+        assert!(conjugate_gradient(&[1.0], |x, y| y[0] = -x[0], |r, z| z.copy_from_slice(r)).is_none());
+        assert!(conjugate_gradient(&[f64::NAN], |_, _| {}, |_, _| {}).is_none());
+        assert_eq!(conjugate_gradient(&[0.0], |_, _| {}, |_, _| {}).unwrap(), vec![0.0]);
+    }
+
     #[test]
     fn svd_reconstructs() {
         let a = [3.0, 1.0, 2.0, -1.0, 4.0, 0.5, 2.0, 2.0, 7.0, 0.1, -3.0, 1.0];
diff --git a/crates/ui-egui/src/app/prefetch.rs b/crates/ui-egui/src/app/prefetch.rs
index e1b953d7b..d351ca411 100644
--- a/crates/ui-egui/src/app/prefetch.rs
+++ b/crates/ui-egui/src/app/prefetch.rs
@@ -406,7 +406,8 @@ impl EffectcraftApp {
         }
         let cur = comp.frame_rate.frame_at(self.session.time()).clamp(wa, wb);
         let fit = self.frames_that_fit(comp, series.scale as f64 / 1000.0).min(n);
-        let slots = (self.frames_parallelism() / 2).max(1);
+        // One thread each (`Frames::request_background`), so every frame thread takes one.
+        let slots = self.frames_parallelism().max(1);
         let mut queued = self.frames.inflight();
         let scale = series.scale as f64 / 1000.0;
         let mut pending = false;
@@ -419,7 +420,7 @@ impl EffectcraftApp {
             if queued >= slots {
                 break;
             }
-            self.request_frame(ItemId(series.comp), f, scale);
+            self.request_frame_background(ItemId(series.comp), f, scale);
             queued += 1;
         }
         if pending {
diff --git a/crates/ui-egui/src/app/viewer_frames.rs b/crates/ui-egui/src/app/viewer_frames.rs
index 3c8632cea..c878fafa4 100644
--- a/crates/ui-egui/src/app/viewer_frames.rs
+++ b/crates/ui-egui/src/app/viewer_frames.rs
@@ -126,12 +126,18 @@ impl EffectcraftApp {
 
     /// Request a prefetch frame render (no-op if cached/in flight).
     pub fn request_frame(&self, comp: ItemId, frame: i64, scale: f64) {
-        self.request_frame_with(comp, frame, scale, false);
+        self.request_frame_with(comp, frame, scale, frames::Frames::request);
     }
 
     /// Request the frame on screen: rendered before any queued prefetch.
     pub fn request_frame_urgent(&self, comp: ItemId, frame: i64, scale: f64) {
-        self.request_frame_with(comp, frame, scale, true);
+        self.request_frame_with(comp, frame, scale, frames::Frames::request_urgent);
+    }
+
+    /// Request a frame nobody waits for (Cache Frames When Idle): rendered on one thread
+    /// (`Frames::request_background`).
+    pub fn request_frame_background(&self, comp: ItemId, frame: i64, scale: f64) {
+        self.request_frame_with(comp, frame, scale, frames::Frames::request_background);
     }
 
     /// Render options of viewer frames of `comp` at `scale`.
@@ -152,15 +158,17 @@ impl EffectcraftApp {
         }
     }
 
-    fn request_frame_with(&self, comp: ItemId, frame: i64, scale: f64, urgent: bool) {
+    fn request_frame_with(
+        &self,
+        comp: ItemId,
+        frame: i64,
+        scale: f64,
+        request: fn(&frames::Frames, &frames::RenderSource, FrameKey, ItemId, Tick, RenderOpts),
+    ) {
         let Some(c) = self.session.project.comp(comp) else { return };
         let key = self.frame_key(comp, frame, scale);
         let t = c.frame_rate.tick_of(frame);
         let opts = self.frame_opts(comp, scale);
-        if urgent {
-            self.frames.request_urgent(&self.render_source(), key, comp, t, opts);
-        } else {
-            self.frames.request(&self.render_source(), key, comp, t, opts);
-        }
+        request(&self.frames, &self.render_source(), key, comp, t, opts);
     }
 }
diff --git a/crates/ui-egui/src/control.rs b/crates/ui-egui/src/control.rs
index e535cc723..f67591bee 100644
--- a/crates/ui-egui/src/control.rs
+++ b/crates/ui-egui/src/control.rs
@@ -9,7 +9,7 @@
 //! - `ui.inspect`: UI state + summary; `ui.elements {prefix?}`: registered widgets (id, label, rect)
 //! - `ui.set {tool?, workspace?, theme?, focused?, viewer?: {zoom, res, pan, grid, …}, timeline?: {pps, start, graphEditor, showModes}}`
 //! - `ui.panel.show {panel}` / `ui.panel.close {panel}`
-//! - `ui.click {id | x,y, button?, count?, modifiers?}` / `ui.move {x,y}` / `ui.scroll {x,y,dx,dy}`
+//! - `ui.click {id | x,y, button?, count?, modifiers?}` / `ui.move {x,y}` / `ui.scroll {x,y,dx,dy,unit?,source?,pinch?}`
 //! - `ui.drag {from:{id|x,y}, to:{id|x,y}, steps?, modifiers?}`: synthetic press-move-release
 //! - `ui.key {key, command?, shift?, alt?, ctrl?}` / `ui.type {text}`
 //! - `ui.viewer.locate {x, y}`: screen point of a comp pixel; `ui.viewer.hit {x, y}`: comp pixel at a screen point
@@ -500,8 +500,9 @@ fn drag(app: &mut EffectcraftApp, p: &Value) -> Outcome {
     Outcome::AfterInput
 }
 
-/// Queues a move to the target point, a wheel event of `dx`, `dy` points with the request's
-/// modifiers, and a released Extra1 button. Replies [`Outcome::AfterInput`].
+/// Queues a move to the target point, a wheel event of `dx`, `dy` (`unit`: points or lines) with
+/// the request's modifiers, a pinch's zoom factor, and a released Extra1 button. Replies
+/// [`Outcome::AfterInput`].
 fn scroll(app: &mut EffectcraftApp, p: &Value) -> Outcome {
     let pos = match point(app, p) {
         Ok(p) => p,
@@ -509,14 +510,23 @@ fn scroll(app: &mut EffectcraftApp, p: &Value) -> Outcome {
     };
     let dx = p.get("dx").and_then(Value::as_f64).unwrap_or(0.0) as f32;
     let dy = p.get("dy").and_then(Value::as_f64).unwrap_or(0.0) as f32;
+    let line = p.get("unit").and_then(Value::as_str) == Some("line");
+    let unit = if line { egui::MouseWheelUnit::Line } else { egui::MouseWheelUnit::Point };
+    // Without a `source`, a scroll in lines is a mouse wheel and one in points comes from an
+    // unnamed device, as on Windows, Linux and the web.
+    let source = match p.get("source").and_then(Value::as_str) {
+        Some("trackpad") => egui::MouseWheelSource::Trackpad,
+        Some("wheel") => egui::MouseWheelSource::Wheel,
+        _ if line => egui::MouseWheelSource::Wheel,
+        _ => egui::MouseWheelSource::Unknown,
+    };
     app.synthetic.push(egui::Event::PointerMoved(pos));
-    app.synthetic.push(egui::Event::MouseWheel {
-        unit: egui::MouseWheelUnit::Point,
-        delta: egui::vec2(dx, dy),
-        modifiers: modifiers(p),
-        phase: egui::TouchPhase::Move,
-        source: egui::MouseWheelSource::Wheel,
-    });
+    if dx != 0.0 || dy != 0.0 {
+        app.synthetic.push(egui::Event::MouseWheel { unit, delta: egui::vec2(dx, dy), modifiers: modifiers(p), phase: egui::TouchPhase::Move, source });
+    }
+    if let Some(pinch) = p.get("pinch").and_then(Value::as_f64).filter(|z| z.is_finite() && *z > 0.0) {
+        app.synthetic.push(egui::Event::Zoom(pinch as f32));
+    }
     app.synthetic.push(egui::Event::PointerButton {
         pos: egui::pos2(-100.0, -100.0),
         button: egui::PointerButton::Extra1,
diff --git a/crates/ui-egui/src/dock.rs b/crates/ui-egui/src/dock.rs
index 054aa3598..8e8fd5eca 100644
--- a/crates/ui-egui/src/dock.rs
+++ b/crates/ui-egui/src/dock.rs
@@ -531,7 +531,8 @@ pub enum DocAction {
 const TAB_PADDING: f32 = 24.0;
 /// Width of the » button that lists the comp tabs with no room in the strip.
 const DOC_OVERFLOW: f32 = 22.0;
-/// Room for the × after the shown comp's name.
+/// Room for the × after a comp's name. Every comp tab keeps it, so a tab keeps its width when it
+/// is shown or hovered.
 const DOC_CLOSE: f32 = 16.0;
 
 /// A comp tab's text: the label swatch, then the name, as the panel tabs with a swatch show it.
@@ -547,24 +548,46 @@ fn text_width(ctx: &egui::Context, job: egui::text::LayoutJob) -> f32 {
     ctx.fonts_mut(|f| f.layout_job(job)).size().x
 }
 
-/// Whether comp tab `doc` carries the ×: the comp the Timeline shows, while it is the group's
-/// shown panel.
-fn has_close(doc: &DocTab, selected: bool) -> bool {
-    selected && doc.active
+/// The width each comp tab asks for in the Timeline group's tab row.
+pub fn doc_widths(ctx: &egui::Context, docs: &[DocTab], font: &egui::FontId) -> Vec<f32> {
+    docs.iter().map(|d| text_width(ctx, doc_job(d, font, egui::Color32::WHITE)) + TAB_PADDING + DOC_CLOSE).collect()
 }
 
-/// The width each comp tab asks for in the Timeline group's tab row.
-pub fn doc_widths(ctx: &egui::Context, docs: &[DocTab], selected: bool, font: &egui::FontId) -> Vec<f32> {
-    docs.iter().map(|d| text_width(ctx, doc_job(d, font, egui::Color32::WHITE)) + TAB_PADDING + if has_close(d, selected) { DOC_CLOSE } else { 0.0 }).collect()
+/// The × of comp tab `doc` at `rect`, clipped to `clip`; true when clicked. `shown` is the comp
+/// the Timeline shows while it is the group's shown panel. Automation:
+/// `panel.tab.Timeline.<comp>.close`, and `panel.tab.Timeline.close` for the shown comp's.
+fn doc_close(
+    ui: &mut egui::Ui,
+    rect: Rect,
+    clip: Rect,
+    doc: &DocTab,
+    shown: bool,
+    style: &craft_ui::docking::DockStyle,
+    reg: &mut crate::automation::Registry,
+) -> bool {
+    let timeline = PanelKind::Timeline.id();
+    let hit = ui.interact(rect.expand(2.0), egui::Id::unique(("comp-tab-close", doc.id)), Sense::click());
+    hit.widget_info(|| egui::WidgetInfo::labeled(egui::Role::Button, hit.enabled(), "Close"));
+    let cc = if hit.hovered() { style.text } else { style.inactive_text };
+    let k = 3.5;
+    let painter = ui.painter().with_clip_rect(clip);
+    painter.line_segment([rect.center() + vec2(-k, -k), rect.center() + vec2(k, k)], Stroke::new(1.2, cc));
+    painter.line_segment([rect.center() + vec2(-k, k), rect.center() + vec2(k, -k)], Stroke::new(1.2, cc));
+    reg.add_response(&format!("panel.tab.{timeline}.{}.close", doc.id), &hit, "Close");
+    if shown {
+        reg.add_response(&format!("panel.tab.{timeline}.close"), &hit, "Close");
+    }
+    hit.clicked()
 }
 
 /// Draw the Timeline's comp tabs into `strip`, the part of the Timeline group's tab row after its
-/// panel tabs. Each is a tab like the panel tabs: the comp's label swatch and name, and × on the
-/// shown comp while the Timeline is the group's shown panel (`selected`). Tabs that do not fit go
-/// to a » menu at the end; the shown comp's tab always stays in the row. Shift+, and Shift+. step
-/// through every open comp. Automation: `panel.tab.Timeline.<comp>`, `panel.tab.Timeline.close`
-/// for the shown comp's ×, `panel.tab.Timeline.more` for », and `panel.tab.Timeline.more.<comp>`
-/// for its items.
+/// panel tabs. Each is a tab like the panel tabs: the comp's label swatch and name, then a ×
+/// that closes the comp's Timeline: always on the shown comp while the Timeline is the group's
+/// shown panel (`selected`), on the other comp tabs while the pointer is over them. Tabs that do
+/// not fit go to a » menu at the end; the shown comp's tab always stays in the row. Shift+, and
+/// Shift+. step through every open comp. Automation: `panel.tab.Timeline.<comp>`, the ×s (see
+/// [`doc_close`]), `panel.tab.Timeline.more` for », and `panel.tab.Timeline.more.<comp>` for its
+/// items.
 pub fn doc_tabs(
     ui: &mut egui::Ui,
     strip: Rect,
@@ -575,7 +598,7 @@ pub fn doc_tabs(
 ) -> Vec<DocAction> {
     let mut out = Vec::new();
     let timeline = PanelKind::Timeline.id();
-    let widths = doc_widths(ui.ctx(), docs, selected, &style.font);
+    let widths = doc_widths(ui.ctx(), docs, &style.font);
     let active = docs.iter().position(|d| d.active).unwrap_or(0);
     let fit = craft_ui::tabs::fit_whole(&widths, active, strip.width(), DOC_OVERFLOW);
     let clip = strip.intersect(ui.clip_rect());
@@ -587,10 +610,9 @@ pub fn doc_tabs(
         x += width;
         let on = selected && doc.active;
         let color = if on { style.text } else { style.inactive_text };
-        let close = has_close(doc, selected);
         let mut job = doc_job(doc, &style.font, color);
         job.wrap = egui::text::TextWrapping {
-            max_width: (tab.width() - TAB_PADDING - if close { DOC_CLOSE } else { 0.0 }).max(0.0),
+            max_width: (tab.width() - TAB_PADDING - DOC_CLOSE).max(0.0),
             max_rows: 1,
             break_anywhere: true,
             overflow_character: Some('\u{2026}'),
@@ -608,17 +630,10 @@ pub fn doc_tabs(
         );
         let resp = if galley.elided { resp.on_hover_text(&doc.title) } else { resp };
         reg.add_response(&format!("panel.tab.{timeline}.{}", doc.id), &resp, &doc.title);
-        if close {
+        // After the tab, so the × takes the clicks over it.
+        if on || ui.rect_contains_pointer(tab.intersect(clip)) {
             let cr = Rect::from_center_size(pos2(label_end + DOC_CLOSE / 2.0, mid), vec2(10.0, 10.0));
-            let hit = ui.interact(cr.expand(2.0), egui::Id::unique(("comp-tab-close", doc.id)), Sense::click());
-            hit.widget_info(|| egui::WidgetInfo::labeled(egui::Role::Button, hit.enabled(), "Close"));
-            let cc = if hit.hovered() { style.text } else { style.inactive_text };
-            let k = 3.5;
-            let painter = ui.painter().with_clip_rect(tab.intersect(clip));
-            painter.line_segment([cr.center() + vec2(-k, -k), cr.center() + vec2(k, k)], Stroke::new(1.2, cc));
-            painter.line_segment([cr.center() + vec2(-k, k), cr.center() + vec2(k, -k)], Stroke::new(1.2, cc));
-            reg.add_response(&format!("panel.tab.{timeline}.close"), &hit, "Close");
-            if hit.clicked() {
+            if doc_close(ui, cr, tab.intersect(clip), doc, on, style, reg) {
                 out.push(DocAction::Close(doc.id));
             }
         }
@@ -654,7 +669,8 @@ pub fn doc_tabs(
     out
 }
 
-/// A viewer lock button (Composition viewers and the Timeline keep their comp while locked).
+/// A viewer lock button (Composition viewers and the Timeline keep their comp while locked): a
+/// closed padlock while locked, an open one while unlocked.
 /// Returns true when clicked. Automation: `panel.tab.<panel>.lock`.
 pub fn lock_button(ui: &mut egui::Ui, rect: Rect, panel: PanelKind, locked: bool, t: &Tokens, reg: &mut crate::automation::Registry) -> bool {
     let resp = ui.interact(rect, egui::Id::unique(("tab-lock", panel.id())), Sense::click());
@@ -665,7 +681,7 @@ pub fn lock_button(ui: &mut egui::Ui, rect: Rect, panel: PanelKind, locked: bool
     } else {
         t.text_faint
     };
-    icons::paint(ui.painter(), rect.shrink(2.0), Icon::Lock, color);
+    icons::paint(ui.painter(), rect.shrink(2.0), if locked { Icon::Lock } else { Icon::LockOpen }, color);
     reg.add_response(&format!("panel.tab.{}.lock", panel.id()), &resp, if locked { "Unlock" } else { "Lock" });
     crate::widgets::focus_outline(ui, &resp, t);
     resp.clicked()
diff --git a/crates/ui-egui/src/dock_ui.rs b/crates/ui-egui/src/dock_ui.rs
index cf180eec0..d17af3b46 100644
--- a/crates/ui-egui/src/dock_ui.rs
+++ b/crates/ui-egui/src/dock_ui.rs
@@ -843,11 +843,11 @@ impl DockContent<PanelKind> for EffectContent<'_> {
         }
     }
 
-    fn group_extra_tabs_width(&self, panels: &[PanelKind], active: &PanelKind, _floating: bool) -> f32 {
+    fn group_extra_tabs_width(&self, panels: &[PanelKind], _active: &PanelKind, _floating: bool) -> f32 {
         if !self.has_doc_tabs(panels) {
             return 0.0;
         }
-        dock::doc_widths(&self.ctx, &self.docs, *active == PanelKind::Timeline, &self.style.font).iter().sum()
+        dock::doc_widths(&self.ctx, &self.docs, &self.style.font).iter().sum()
     }
 
     /// The Timeline's comp tabs, after its group's panel tabs whichever panel is shown.
diff --git a/crates/ui-egui/src/frames.rs b/crates/ui-egui/src/frames.rs
index b524b5959..883cbf172 100644
--- a/crates/ui-egui/src/frames.rs
+++ b/crates/ui-egui/src/frames.rs
@@ -1,7 +1,8 @@
 //! Background frame rendering and the RAM preview cache.
 //!
 //! Frames render on a dedicated thread pool from immutable `Arc<Project>` snapshots, so the UI
-//! never waits for the compositor. Results land in a memory-budgeted cache keyed by the comp's
+//! never waits for the compositor (a playing preview's frames and idle caching on one thread
+//! each, so the frames started first are done first). Results land in a memory-budgeted cache keyed by the comp's
 //! *content* ([`comp_content`]: the comp and everything it uses), frame, scale, view and render
 //! options; the timeline draws the cached range as the green cache bar. An edit keeps the frames
 //! of every comp it doesn't touch, and undo finds the frames of the state it returns to.
@@ -456,6 +457,10 @@ pub struct Frames {
     #[cfg(not(target_arch = "wasm32"))]
     /// None if the OS refused the threads: jobs then go to rayon's global pool.
     pool: Option<rayon::ThreadPool>,
+    #[cfg(not(target_arch = "wasm32"))]
+    /// One thread each, for a playing preview's frames and idle caching (see [`Queue::idle_lanes`]). Empty if
+    /// the OS refused the threads: those frames then render on `pool` too.
+    lanes: Vec<rayon::ThreadPool>,
     ctx: Option<egui::Context>,
     /// Render time of the last viewer (urgent) frame in ms, for the Info panel / perf readout.
     pub last_ms: Arc<Mutex<f64>>,
@@ -484,10 +489,25 @@ impl Default for Frames {
     fn default() -> Self {
         #[cfg(not(target_arch = "wasm32"))]
         let threads = std::thread::available_parallelism().map(|n| n.get()).unwrap_or(4).clamp(2, 16);
+        #[cfg(not(target_arch = "wasm32"))]
+        let lanes: Vec<rayon::ThreadPool> = (0..threads)
+            .map_while(|i| {
+                rayon::ThreadPoolBuilder::new()
+                    .num_threads(1)
+                    .thread_name(move |_| format!("ec-preview-{i}"))
+                    .panic_handler(|_| log::error!("a frame render panicked; that frame was skipped"))
+                    .build()
+                    .ok()
+            })
+            .collect();
+        #[cfg(not(target_arch = "wasm32"))]
+        let queue = Queue { idle_lanes: (0..lanes.len()).collect(), lanes: lanes.len(), ..Default::default() };
+        #[cfg(target_arch = "wasm32")]
+        let queue = Queue::default();
         Frames {
             cache: Arc::new(Mutex::new(Cache { map: HashMap::new(), order: VecDeque::new(), bytes: 0, gpu_bytes: 0, budget: 3 << 30, gpu_budget: GPU_BUDGET, playhead: None, scale: None })),
             inflight: Arc::new(Mutex::new(HashSet::new())),
-            queue: Arc::new(Mutex::new(Queue::default())),
+            queue: Arc::new(Mutex::new(queue)),
             #[cfg(not(target_arch = "wasm32"))]
             // A panicking job would abort the whole process (rayon's default for `spawn`): log it
             // and lose only that frame (the panic hook has logged the message).
@@ -497,6 +517,8 @@ impl Default for Frames {
                 .panic_handler(|_| log::error!("a frame render panicked; that frame was skipped"))
                 .build()
                 .ok(),
+            #[cfg(not(target_arch = "wasm32"))]
+            lanes,
             ctx: None,
             last_ms: Arc::new(Mutex::new(0.0)),
             content_keys: Arc::default(),
@@ -911,26 +933,77 @@ impl Frames {
             c.playhead = playhead;
         }
         let Ok(mut q) = self.queue.lock() else { return };
+        // A preview starting or stopping moves the queued prefetch frames between the lanes and
+        // the pool (see [`Queue::idle_lanes`]).
+        #[cfg(not(target_arch = "wasm32"))]
+        let moved = q.playhead.is_some() != playhead.is_some();
         q.playhead = playhead;
-        let Some(p) = playhead else { return };
-        let Ok(mut inf) = self.inflight.lock() else { return };
-        q.jobs.retain(|j| {
-            let gone = !j.urgent && j.key.same_series(&p.series) && p.ahead(&j.key).is_none();
-            if gone {
-                inf.remove(&j.key);
+        if let Some(p) = playhead
+            && let Ok(mut inf) = self.inflight.lock()
+        {
+            q.jobs.retain(|j| {
+                let gone = !j.urgent && j.key.same_series(&p.series) && p.ahead(&j.key).is_none();
+                if gone {
+                    inf.remove(&j.key);
+                }
+                !gone
+            });
+        }
+        #[cfg(not(target_arch = "wasm32"))]
+        if moved {
+            self.start_lanes(&mut q, usize::MAX);
+            let pool_jobs = q.jobs.iter().filter(|j| !q.on_lane(j)).count().min(self.parallelism());
+            drop(q);
+            for _ in 0..pool_jobs {
+                self.start_pool();
             }
-            !gone
-        });
+        }
+    }
+
+    /// Start up to `n` idle lanes on the queued jobs (see [`Queue::idle_lanes`]).
+    #[cfg(not(target_arch = "wasm32"))]
+    fn start_lanes(&self, q: &mut Queue, n: usize) {
+        if self.remote.is_some() {
+            return;
+        }
+        let jobs = q.jobs.iter().filter(|j| q.on_lane(j)).count();
+        for _ in 0..n.min(jobs) {
+            let Some(lane) = q.idle_lanes.pop() else { break };
+            let Some(pool) = self.lanes.get(lane) else { break };
+            let w = self.worker();
+            pool.spawn(move || w.drain(Some(lane)));
+        }
+    }
+
+    /// Have a pool thread render the queued jobs that are the pool's.
+    #[cfg(not(target_arch = "wasm32"))]
+    fn start_pool(&self) {
+        if self.remote.is_some() {
+            return;
+        }
+        let w = self.worker();
+        let job = move || w.drain(None);
+        match &self.pool {
+            Some(pool) => pool.spawn(job),
+            None => rayon::spawn(job),
+        }
     }
 
     /// Queue a prefetch frame (no-op if cached or already queued/rendering).
     pub fn request(&self, src: &RenderSource, key: FrameKey, comp: ItemId, t: Tick, opts: RenderOpts) {
-        self.request_with(src, key, comp, t, opts, false);
+        self.request_with(src, key, comp, t, opts, Want::Prefetch);
+    }
+
+    /// Queue a frame nobody waits for (Cache Frames When Idle): as [`Frames::request`], but it
+    /// renders on a lane, one thread, and leaves the pool to the viewer's frame (see
+    /// [`Queue::idle_lanes`]).
+    pub fn request_background(&self, src: &RenderSource, key: FrameKey, comp: ItemId, t: Tick, opts: RenderOpts) {
+        self.request_with(src, key, comp, t, opts, Want::Background);
     }
 
     /// Queue the frame the viewer is showing: it jumps ahead of every prefetch job.
     pub fn request_urgent(&self, src: &RenderSource, key: FrameKey, comp: ItemId, t: Tick, opts: RenderOpts) {
-        self.request_with(src, key, comp, t, opts, true);
+        self.request_with(src, key, comp, t, opts, Want::Viewer);
     }
 
     /// An urgent (viewer) frame is queued or rendering.
@@ -938,7 +1011,8 @@ impl Frames {
         self.queue.lock().map(|q| q.urgent_running > 0 || q.jobs.iter().any(|j| j.urgent)).unwrap_or(false)
     }
 
-    fn request_with(&self, src: &RenderSource, key: FrameKey, comp: ItemId, t: Tick, opts: RenderOpts, urgent: bool) {
+    fn request_with(&self, src: &RenderSource, key: FrameKey, comp: ItemId, t: Tick, opts: RenderOpts, want: Want) {
+        let urgent = want == Want::Viewer;
         // The frame on screen sets the scale evictions keep: a prefetch or a passive viewer at
         // another zoom must not evict the active viewer's frames.
         let cached = self
@@ -990,22 +1064,32 @@ impl Frames {
             }
         }
         if !inf.insert(key) {
+            drop(inf);
+            drop(q);
+            // Queued for a lane and now the viewer's frame: it is the pool's.
+            #[cfg(not(target_arch = "wasm32"))]
+            if urgent {
+                self.start_pool();
+            }
             return;
         }
         q.seq += 1;
         let seq = q.seq;
-        q.jobs.push(Job { key, src: src.clone(), comp, t, opts, urgent, seq, cancel: Arc::default() });
+        let job = Job { key, src: src.clone(), comp, t, opts, urgent, background: want == Want::Background, seq, cancel: Arc::default() };
+        // A lane's frame: a busy lane takes the next job when it is done, an idle one starts now.
+        #[cfg(not(target_arch = "wasm32"))]
+        let on_lane = q.on_lane(&job);
+        q.jobs.push(job);
+        #[cfg(not(target_arch = "wasm32"))]
+        if on_lane {
+            self.start_lanes(&mut q, 1);
+        }
         drop(inf);
         drop(q);
+        // One spawn per job; each spawn renders whichever queued jobs matter most right now.
         #[cfg(not(target_arch = "wasm32"))]
-        if self.remote.is_none() {
-            let w = self.worker();
-            // One spawn per job; each spawn renders whichever queued jobs matter most right now.
-            let job = move || w.drain();
-            match &self.pool {
-                Some(pool) => pool.spawn(job),
-                None => rayon::spawn(job),
-            }
+        if !on_lane {
+            self.start_pool();
         }
         #[cfg(target_arch = "wasm32")]
         if let Some(ctx) = &self.ctx {
@@ -1147,7 +1231,7 @@ impl Frames {
         }
         let t0 = web_time::Instant::now();
         let w = self.worker();
-        while w.run_next() {
+        while w.run_next(None) {
             if t0.elapsed() >= budget {
                 break;
             }
@@ -1195,22 +1279,29 @@ impl Worker {
     /// every UI frame, so renders piled up on every thread until memory ran out (#647). A spawn
     /// that lands inside a render returns at once instead; the render below it takes the queued
     /// jobs when it is done, so each thread renders one frame at a time.
+    ///
+    /// `lane`: the lane this runs on (see [`Queue::idle_lanes`]), `None` on the pool.
     #[cfg(not(target_arch = "wasm32"))]
-    fn drain(&self) {
+    fn drain(&self, lane: Option<usize>) {
         if DRAINING.get() {
             return;
         }
         DRAINING.set(true);
         let _reset = Draining;
-        while self.run_next() {}
+        while self.run_next(lane) {}
     }
 
-    /// Render the queued job that matters most right now. `false` when the queue was empty.
-    fn run_next(&self) -> bool {
+    /// Render the queued job that matters most right now, on lane `lane` (`None`: on
+    /// the pool, or the UI thread). `false` when the queue had no job for it; the lane is then
+    /// idle again.
+    fn run_next(&self, lane: Option<usize>) -> bool {
         let Worker { queue, content_keys, .. } = self;
         let job = {
             let Ok(mut q) = queue.lock() else { return false };
-            let Some(i) = q.best() else { return false };
+            let Some(i) = q.next(lane.is_some()) else {
+                q.idle_lanes.extend(lane);
+                return false;
+            };
             let job = q.jobs.swap_remove(i);
             q.running.insert(job.key);
             if job.urgent {
@@ -1405,6 +1496,14 @@ impl Worker {
     }
 }
 
+/// Who asked for a frame (see [`Frames::request_with`]).
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Want {
+    Viewer,
+    Prefetch,
+    Background,
+}
+
 struct Job {
     key: FrameKey,
     src: RenderSource,
@@ -1412,6 +1511,8 @@ struct Job {
     t: Tick,
     opts: RenderOpts,
     urgent: bool,
+    /// Nobody waits for it (see [`Frames::request_background`]).
+    background: bool,
     seq: u64,
     /// Set when the viewer no longer waits for this frame (see [`Frames::request_urgent`]).
     cancel: Arc<AtomicBool>,
@@ -1434,18 +1535,45 @@ struct Queue {
     seq: u64,
     /// The playing preview, if any: its prefetch renders nearest first.
     playhead: Option<Playhead>,
+    /// How many lanes there are, and the ones not rendering. A lane is one thread that renders
+    /// one frame at a time. The frames of a playing preview and the frames nobody waits for
+    /// (Cache Frames When Idle) render on the lanes; the pool keeps the viewer's frame and the
+    /// few frames prefetched around it while paused. On the pool a frame's parallel work is
+    /// shared: a thread that took a piece of one frame and waited inside it started rendering
+    /// the queued frames on top, and went back to its piece only once the queue was empty. The
+    /// frames a preview started first, the ones right ahead of the playhead, were done last:
+    /// the preview stood still on a gap while the frames further ahead turned green. Idle
+    /// caching left the same gaps, and held up the viewer's frame when it shared a piece.
+    lanes: usize,
+    idle_lanes: Vec<usize>,
 }
 
 impl Queue {
+    /// Whether `j` renders on a lane (else on the pool).
+    fn on_lane(&self, j: &Job) -> bool {
+        self.lanes > 0 && !j.urgent && (j.background || self.playhead.is_some())
+    }
+
+    /// The job a lane (`lane`) or the pool renders next: the [`Queue::best`] of its own.
+    fn next(&self, lane: bool) -> Option<usize> {
+        self.best_of(|j| self.on_lane(j) == lane)
+    }
+
     /// The job that matters most: urgent first (newest), then, while a preview plays, the
     /// prefetch frame it reaches first, then prefetch in request order. In request order alone,
     /// frames asked for again after an eviction (the ones right ahead of the playhead) waited
     /// behind every frame further ahead (#595).
     fn best(&self) -> Option<usize> {
+        self.best_of(|_| true)
+    }
+
+    /// [`Queue::best`] among the jobs `of` accepts.
+    fn best_of(&self, of: impl Fn(&Job) -> bool) -> Option<usize> {
         let p = self.playhead.as_ref();
         self.jobs
             .iter()
             .enumerate()
+            .filter(|(_, j)| of(j))
             .max_by_key(|(_, j)| {
                 let near = if j.urgent { None } else { p.and_then(|p| p.ahead(&j.key)) };
                 (j.urgent, near.is_some(), near.map_or(0, |d| -d), if j.urgent { j.seq as i64 } else { -(j.seq as i64) })
diff --git a/crates/ui-egui/src/frames/tests.rs b/crates/ui-egui/src/frames/tests.rs
index a2603dfec..49f77a6cf 100644
--- a/crates/ui-egui/src/frames/tests.rs
+++ b/crates/ui-egui/src/frames/tests.rs
@@ -437,7 +437,9 @@ fn a_newer_viewer_frame_drops_the_ones_still_waiting() {
         gpu_display: false,
         disk: None,
     };
-    let request = |k: FrameKey, urgent: bool| f.request_with(&src, k, ItemId(k.comp), Tick::ZERO, RenderOpts::default(), urgent);
+    let request = |k: FrameKey, urgent: bool| {
+        f.request_with(&src, k, ItemId(k.comp), Tick::ZERO, RenderOpts::default(), if urgent { Want::Viewer } else { Want::Prefetch })
+    };
     let other = FrameKey { comp: 2, ..key(1, 0, 0) };
     request(other, true);
     request(key(1, 20, 0), false);
@@ -558,6 +560,131 @@ fn prefetch_renders_the_frames_the_playhead_reaches_first() {
     assert_eq!(f.inflight(), 6, "frame 5, behind the playhead, is no longer in flight");
 }
 
+/// A decoder that works in parallel, as the renderer does, in a comp that shows it.
+#[derive(Default)]
+struct ParallelClip {
+    started: std::sync::atomic::AtomicUsize,
+    /// Frames started by the time frame 1 was done.
+    started_at_first: std::sync::atomic::AtomicUsize,
+}
+
+impl FootageSource for ParallelClip {
+    fn frame(&self, _: ItemId, _: &effectcraft_engine::project::Footage, t: Tick) -> Option<Arc<effectcraft_engine::render::Image>> {
+        self.started.fetch_add(1, Ordering::SeqCst);
+        (0..16).into_par_iter().for_each(|_| (0..4).into_par_iter().for_each(|_| std::thread::sleep(std::time::Duration::from_millis(1))));
+        if effectcraft_engine::time::FrameRate::FPS_30.frame_at(t) == 1 {
+            self.started_at_first.store(self.started.load(Ordering::SeqCst), Ordering::SeqCst);
+        }
+        Some(Arc::new(effectcraft_engine::render::Image::new(4, 4)))
+    }
+}
+
+/// A 10 s comp of a [`ParallelClip`]: the frame cache, the clip, the render source, the comp
+/// and the key of its frame 0.
+fn parallel_clip() -> (Frames, Arc<ParallelClip>, RenderSource, ItemId, FrameKey) {
+    use effectcraft_engine::Session;
+    use effectcraft_engine::project::{Footage, FootageKind};
+    use effectcraft_engine::time::FrameRate;
+    use serde_json::json;
+    let mut s = Session::default();
+    let cid = ItemId(s.execute("comp.new", json!({"name": "A", "width": 8, "height": 8, "duration": 10})).unwrap()["comp"].as_u64().unwrap());
+    let clip = Footage {
+        kind: FootageKind::Video,
+        width: 4,
+        height: 4,
+        has_video: true,
+        frame_rate: FrameRate::FPS_30,
+        duration: Tick::from_seconds_f64(10.0),
+        ..Default::default()
+    };
+    let item = Arc::make_mut(&mut s.project).add_item("clip.mov", Default::default(), None, ItemKind::Footage(clip));
+    s.execute("layer.addItem", json!({"item": item.0})).unwrap();
+    let footage = Arc::new(ParallelClip::default());
+    let src = RenderSource {
+        project: s.project.clone(),
+        footage: footage.clone(),
+        expr: None,
+        layer_cache: Arc::default(),
+        gpu: None,
+        gpu_display: false,
+        disk: None,
+    };
+    let f = Frames::default();
+    let series = FrameKey { revision: s.revision, content: f.content_of(&s.project, s.revision, cid), comp: cid.0, frame: 0, scale: 1000, view: 0, opts: 0 };
+    (f, footage, src, cid, series)
+}
+
+fn wait_for_renders(f: &Frames) {
+    for _ in 0..8000 {
+        if f.inflight() == 0 {
+            break;
+        }
+        std::thread::sleep(std::time::Duration::from_millis(5));
+    }
+    assert_eq!(f.inflight(), 0, "every queued frame rendered");
+}
+
+/// A playing preview's frames render side by side, and each works in parallel: a render
+/// waiting for its own parallel work took over pieces of the frames started after it, and
+/// its frame was done only once theirs were. The frames right ahead of the playhead, started
+/// first, came last: the preview stood still while the frames further ahead turned green.
+/// Cache Frames When Idle left the same gaps.
+#[test]
+fn frames_started_first_are_done_first() {
+    use effectcraft_engine::time::FrameRate;
+    for playing in [true, false] {
+        let (f, footage, src, cid, series) = parallel_clip();
+        let frames = 60;
+        if playing {
+            f.set_playhead(Some(Playhead { series, cur: 0, start: 0, end: 299, step: 1, looping: false }));
+        }
+        for frame in 1..=frames {
+            let (key, t) = (FrameKey { frame, ..series }, FrameRate::FPS_30.tick_of(frame));
+            if playing {
+                f.request(&src, key, cid, t, RenderOpts::default());
+            } else {
+                f.request_background(&src, key, cid, t, RenderOpts::default());
+            }
+            if frame == 1 {
+                // Its parallel work has started (and idle threads have taken pieces of it).
+                std::thread::sleep(std::time::Duration::from_millis(3));
+            }
+        }
+        wait_for_renders(&f);
+        assert_eq!(f.cached_frames(&series).len(), frames as usize);
+        let before = footage.started_at_first.load(Ordering::SeqCst);
+        assert!(before <= 2 * f.parallelism(), "{before} frames were started before the first one was done (playing: {playing})");
+    }
+}
+
+/// Prefetch frames queued when a preview starts or stops, or that become the viewer's
+/// frame, still render: they change hands between the lanes and the pool.
+#[test]
+fn queued_frames_render_when_a_preview_starts_or_stops() {
+    use effectcraft_engine::time::FrameRate;
+    let (f, _, src, cid, series) = parallel_clip();
+    let playhead = Playhead { series, cur: 0, start: 0, end: 299, step: 1, looping: false };
+    let request = |frames: std::ops::Range<i64>| {
+        for frame in frames {
+            f.request(&src, FrameKey { frame, ..series }, cid, FrameRate::FPS_30.tick_of(frame), RenderOpts::default());
+        }
+    };
+    // Queued for the pool, then a preview starts.
+    request(1..40);
+    f.set_playhead(Some(playhead));
+    // Queued for the lanes, then the preview stops.
+    request(40..80);
+    f.set_playhead(None);
+    wait_for_renders(&f);
+    // Queued for the lanes, then the viewer shows one of them.
+    for frame in 80..120 {
+        f.request_background(&src, FrameKey { frame, ..series }, cid, FrameRate::FPS_30.tick_of(frame), RenderOpts::default());
+    }
+    f.request_urgent(&src, FrameKey { frame: 119, ..series }, cid, FrameRate::FPS_30.tick_of(119), RenderOpts::default());
+    wait_for_renders(&f);
+    assert_eq!(f.cached_frames(&series).len(), 119);
+}
+
 /// The cache is full. A zoom (or preview-resolution) change left the frames of the old
 /// size to the plain least-recently-shown order, so the frames of the zoom the viewer is back
 /// at went before the ones of the abandoned zoom. The other size's frames go first, then the
diff --git a/crates/ui-egui/src/header.rs b/crates/ui-egui/src/header.rs
index 3eee89453..8710f1f9a 100644
--- a/crates/ui-egui/src/header.rs
+++ b/crates/ui-egui/src/header.rs
@@ -12,6 +12,7 @@ use crate::widgets;
 use crate::{Dialog, EffectcraftApp};
 use effectcraft_color::BlendMode;
 use effectcraft_engine::commands::shape_tool::{PaintKind, ToolPaint};
+use effectcraft_engine::geom::vec2 as gv2;
 use effectcraft_engine::project::{LayerId, LayerSource, PropGroup};
 use effectcraft_engine::viewer as vw;
 
@@ -93,9 +94,11 @@ fn tool_slot(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter, si:
         ));
     }
     app.auto.add_response(&format!("tools.{cur:?}"), &resp, cur.label());
+    // The drawn tooltip asks the catalog; the automation label above keeps the English name.
+    let label = crate::i18n::tr(cur.label());
     let tip = match cur.shortcut() {
-        Some(s) => format!("{} ({})", cur.label(), crate::menus::shortcut_text(s)),
-        None => cur.label().to_string(),
+        Some(s) => format!("{} ({})", label, crate::menus::shortcut_text(s)),
+        None => label.to_string(),
     };
     let resp = resp.on_hover_text(tip);
     let held = ui.data(|d| d.get_temp::<egui::Id>(held_id)) == Some(id);
@@ -109,6 +112,11 @@ fn tool_slot(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter, si:
         && let Err(e) = crate::menus::invoke(app, ui.ctx(), "layer.centerAnchor", json!({}))
     {
         app.ui.status = e;
+    } else if resp.double_clicked()
+        && let Some((id, params)) = create_on_double_click(app, cur)
+        && let Err(e) = crate::menus::invoke(app, ui.ctx(), id, params)
+    {
+        app.ui.status = e;
     }
     if slot.len() > 1 {
         slot_flyout(app, ui, si, slot, &resp, held_id);
@@ -139,7 +147,7 @@ fn slot_flyout(app: &mut EffectcraftApp, ui: &mut egui::Ui, si: usize, slot: &[T
     let close_behavior = if held && resp.clicked() { egui::PopupCloseBehavior::IgnoreClicks } else { egui::PopupCloseBehavior::CloseOnClickOutside };
     egui::Popup::menu(resp).style(crate::widgets::menu_style).open_memory(command).close_behavior(close_behavior).show(|ui| {
         for tool in slot.iter() {
-            let row = ui.selectable_label(app.ui.tool == *tool, tool.label());
+            let row = ui.selectable_label(app.ui.tool == *tool, crate::i18n::tr(tool.label()));
             app.auto.add(&format!("tools.select.{tool:?}"), row.rect, tool.label());
             if row.clicked() {
                 app.ui.tool = *tool;
@@ -374,6 +382,58 @@ fn workspace_tabs(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter
     }
 }
 
+/// Double-clicking a creation tool in the Tools bar makes an instance of what it draws, as in
+/// After Effects (#1072): a text layer from the Type tools; from the shape tools, a shape that
+/// fills the comp — into the selected shape layer's Contents, as a mask on the selected layer
+/// (any non-shape layer, or Tool Creates Mask), or as a new shape layer when neither applies.
+fn create_on_double_click(app: &EffectcraftApp, tool: Tool) -> Option<(&'static str, serde_json::Value)> {
+    match tool {
+        // `invoke` turns empty params into an insertion point in the comp centre that starts
+        // editing (#866), which is what double-clicking the Type tool should do.
+        Tool::Type | Tool::TypeVertical => Some(("layer.newText", json!({}))),
+        Tool::Rectangle | Tool::RoundedRect | Tool::Ellipse | Tool::Polygon | Tool::Star => {
+            let kind = match tool {
+                Tool::Rectangle => "rect",
+                Tool::RoundedRect => "rounded",
+                Tool::Ellipse => "ellipse",
+                Tool::Polygon => "polygon",
+                _ => "star",
+            };
+            // Without a comp the command still runs and reports its error on the status line.
+            let Some(comp) = app.session.active_comp() else {
+                return Some(("shape.newShape", json!({"kind": kind})));
+            };
+            let (cw, ch) = (comp.width as f64, comp.height as f64);
+            // Rectangles and ellipses fill the comp; a Polystar's Outer Radius is half the comp
+            // height (Inner Radius: a quarter of it), so it gets a comp-height square.
+            let (w, h) = if matches!(tool, Tool::Polygon | Tool::Star) { (ch, ch) } else { (cw, ch) };
+            // A mask on the selected layer: any non-shape layer (the tool switches to Mask by
+            // itself), or a shape layer while Tool Creates Mask is on — as dragging does.
+            let sel = app.session.state.selected_layers.first().copied().and_then(|id| comp.layer(id));
+            if let Some(l) = sel.filter(|l| l.source.is_av() && (app.session.state.shape_tool.creates_mask || !matches!(l.source, LayerSource::Shape))) {
+                // The box in layer space, so a moved, scaled or rotated layer still gets a
+                // comp-filling mask: all four corners are mapped, and their bounds are the
+                // smallest axis-aligned box around the comp box.
+                let ctx = effectcraft_engine::render::EvalCtx::new(&app.session.project, app.session.active_comp_id()?, comp, app.session.time());
+                let inv = ctx.layer_to_comp(l).0.inverse().unwrap_or(effectcraft_engine::geom::Mat3::IDENTITY);
+                let (x0, y0, x1, y1) = (cw / 2.0 - w / 2.0, ch / 2.0 - h / 2.0, cw / 2.0 + w / 2.0, ch / 2.0 + h / 2.0);
+                let pts = [gv2(x0, y0), gv2(x1, y0), gv2(x1, y1), gv2(x0, y1)].map(|p| inv.apply(p));
+                let (mut lo, mut hi) = ([f64::INFINITY; 2], [f64::NEG_INFINITY; 2]);
+                for p in pts {
+                    lo = [lo[0].min(p.x), lo[1].min(p.y)];
+                    hi = [hi[0].max(p.x), hi[1].max(p.y)];
+                }
+                let rect = [lo[0], lo[1], hi[0] - lo[0], hi[1] - lo[1]];
+                return Some(("layer.addMask", json!({"layer": l.id.0, "shape": kind, "rect": rect})));
+            }
+            // Into the selected shape layer's Contents, else a new shape layer (the engine's own
+            // target), painted with the Tools bar's Fill and Stroke.
+            Some(("shape.newShape", json!({"kind": kind, "size": [w, h]})))
+        }
+        _ => None,
+    }
+}
+
 /// The Snapping options menu beside the checkbox: After Effects' Snap Edges Extended and Snap to
 /// Features in Collapsed Compositions and Text Layers (`view.snappingOptions`).
 fn snapping_options(app: &mut EffectcraftApp, ui: &mut egui::Ui, r: Rect) {
@@ -834,4 +894,254 @@ mod tests {
         frame(&mut app, &ctx, 2.1, vec![]);
         assert!(!app.auto.elements.iter().any(|w| w.id == "tools.select.TypeVertical"));
     }
+
+    /// Double-clicking a creation tool in the Tools bar makes an instance of what it draws
+    /// (#1072): with nothing selected a shape layer whose shape fills the comp, into the selected
+    /// shape layer's Contents, a mask on a non-shape layer, a text layer from the Type tools.
+    /// Tools that create nothing stay quiet.
+    #[test]
+    fn double_clicking_creation_tools_makes_instances() {
+        let mut s = effectcraft_engine::Session::default();
+        s.execute("comp.new", json!({"width": 640, "height": 360, "duration": 2})).unwrap();
+        let mut app = EffectcraftApp::new(s);
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &app.tokens, crate::i18n::language(&app));
+        frame(&mut app, &ctx, 0.0, vec![]);
+        frame(&mut app, &ctx, 0.1, vec![]);
+        let pointer = |pos, pressed| egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed, modifiers: Default::default() };
+        // Both click pairs in one frame, as egui counts a double-click.
+        let double_click = |app: &mut EffectcraftApp, ctx: &egui::Context, t: f64, id: &str| {
+            let e = app.auto.elements.iter().find(|w| w.id == id).unwrap_or_else(|| panic!("no {id}"));
+            let at = egui::pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+            frame(app, ctx, t, vec![egui::Event::PointerMoved(at), pointer(at, true), pointer(at, false), pointer(at, true), pointer(at, false)]);
+        };
+        // Nothing selected: a shape layer with a Rectangle Path 1 the size of the comp.
+        double_click(&mut app, &ctx, 1.0, "tools.Rectangle");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 1, "the double-click made a layer");
+            let l = &comp.layers[0];
+            assert!(matches!(l.source, LayerSource::Shape), "a shape layer");
+            let size = l.props.prop("contents/Rectangle 1/contents/Rectangle Path 1/size").expect("Rectangle Path 1");
+            assert_eq!(size.value.as_vec2(), [640.0, 360.0], "the rectangle fills the comp");
+        }
+        // The shape layer is selected: the Ellipse goes on top of its Contents, no new layer.
+        app.ui.slot_tools[8] = Tool::Ellipse;
+        frame(&mut app, &ctx, 1.05, vec![]);
+        double_click(&mut app, &ctx, 2.0, "tools.Ellipse");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 1, "into the selected shape layer's Contents");
+            let l = &comp.layers[0];
+            assert!(l.props.prop("contents/Ellipse 1/contents/Ellipse Path 1/size").is_some(), "the new ellipse is on top");
+            assert!(l.props.prop("contents/Rectangle 1/contents/Rectangle Path 1/size").is_some(), "the rectangle still stands");
+        }
+        // The Type tool: a text layer above the selection, editing started (an insertion point, #866).
+        double_click(&mut app, &ctx, 3.0, "tools.Type");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 2);
+            assert!(matches!(comp.layers[0].source, LayerSource::Text));
+            assert!(app.session.state.text_edit.is_some(), "the text layer is being edited");
+        }
+        // A non-shape layer is selected, so the Rectangle becomes a comp-filling mask on it.
+        app.ui.slot_tools[8] = Tool::Rectangle;
+        frame(&mut app, &ctx, 3.05, vec![]);
+        double_click(&mut app, &ctx, 4.0, "tools.Rectangle");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 2, "a mask, not a layer");
+            let p = comp.layers[0].props.prop("masks/Mask 1/path").expect("Mask 1");
+            let sh = p.value.as_path().expect("a mask path");
+            let b = effectcraft_path::bounds(&[effectcraft_path::to_kurbo(sh)]).expect("bounds");
+            // The text layer is anchored top-left and centred in the comp: layer = comp - centre.
+            for (got, want) in [(b.x0, -320.0), (b.y0, -180.0), (b.x1, 320.0), (b.y1, 180.0)] {
+                assert!((got - want).abs() < 1.0, "the mask fills the comp: {got} vs {want}");
+            }
+        }
+        // A tool that creates nothing: no layer, no error.
+        double_click(&mut app, &ctx, 5.0, "tools.Hand");
+        assert_eq!(app.session.active_comp().unwrap().layers.len(), 2, "the Hand tool creates nothing");
+        assert!(app.ui.status.is_empty(), "{}", app.ui.status);
+        // Without a comp the command fails with the status line, never a panic.
+        let mut bare = EffectcraftApp::new(effectcraft_engine::Session::default());
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &bare.tokens, crate::i18n::language(&bare));
+        frame(&mut bare, &ctx, 0.0, vec![]);
+        frame(&mut bare, &ctx, 0.1, vec![]);
+        double_click(&mut bare, &ctx, 1.0, "tools.Rectangle");
+        assert!(!bare.ui.status.is_empty(), "no comp: a status message, not a crash");
+    }
+
+    /// #1765: a double-click on the Ellipse tool with nothing selected makes its own shape layer
+    /// the size of the comp, as the Rectangle does.
+    #[test]
+    fn double_click_ellipse_with_no_selection_makes_a_layer() {
+        let mut s = effectcraft_engine::Session::default();
+        s.execute("comp.new", json!({"width": 640, "height": 360, "duration": 2})).unwrap();
+        let mut app = EffectcraftApp::new(s);
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &app.tokens, crate::i18n::language(&app));
+        frame(&mut app, &ctx, 0.0, vec![]);
+        frame(&mut app, &ctx, 0.1, vec![]);
+        app.ui.slot_tools[8] = Tool::Ellipse;
+        frame(&mut app, &ctx, 1.0, vec![]);
+        let pointer = |pos, pressed| egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed, modifiers: Default::default() };
+        let e = app.auto.elements.iter().find(|w| w.id == "tools.Ellipse").unwrap_or_else(|| panic!("no tools.Ellipse"));
+        let at = egui::pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+        frame(&mut app, &ctx, 1.1, vec![egui::Event::PointerMoved(at), pointer(at, true), pointer(at, false), pointer(at, true), pointer(at, false)]);
+        let comp = app.session.active_comp().unwrap();
+        assert_eq!(comp.layers.len(), 1, "the double-click made a layer");
+        let l = &comp.layers[0];
+        assert!(matches!(l.source, LayerSource::Shape), "a shape layer");
+        let size = l.props.prop("contents/Ellipse 1/contents/Ellipse Path 1/size").expect("Ellipse Path 1");
+        assert_eq!(size.value.as_vec2(), [640.0, 360.0], "the ellipse fills the comp");
+        assert!(app.ui.status.is_empty(), "{}", app.ui.status);
+    }
+
+    /// Tool Creates Mask on (#1072): a double-click on a shape tool masks the selected shape
+    /// layer instead of adding to its Contents.
+    #[test]
+    fn double_click_masks_a_shape_layer_while_tool_creates_mask() {
+        let mut s = effectcraft_engine::Session::default();
+        s.execute("comp.new", json!({"width": 640, "height": 360, "duration": 2})).unwrap();
+        let mut app = EffectcraftApp::new(s);
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &app.tokens, crate::i18n::language(&app));
+        frame(&mut app, &ctx, 0.0, vec![]);
+        frame(&mut app, &ctx, 0.1, vec![]);
+        let pointer = |pos, pressed| egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed, modifiers: Default::default() };
+        let double_click = |app: &mut EffectcraftApp, ctx: &egui::Context, t: f64, id: &str| {
+            let e = app.auto.elements.iter().find(|w| w.id == id).unwrap_or_else(|| panic!("no {id}"));
+            let at = egui::pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+            frame(app, ctx, t, vec![egui::Event::PointerMoved(at), pointer(at, true), pointer(at, false), pointer(at, true), pointer(at, false)]);
+        };
+        // A shape layer, selected by the double-click that made it.
+        double_click(&mut app, &ctx, 1.0, "tools.Rectangle");
+        assert_eq!(app.session.active_comp().unwrap().layers.len(), 1);
+        app.session.state.shape_tool.creates_mask = true;
+        app.ui.slot_tools[8] = Tool::Ellipse;
+        frame(&mut app, &ctx, 1.05, vec![]);
+        double_click(&mut app, &ctx, 2.0, "tools.Ellipse");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 1, "a mask, not a second shape layer");
+            let l = &comp.layers[0];
+            assert!(l.props.prop("masks/Mask 1/path").is_some(), "an ellipse mask");
+            assert!(l.props.prop("contents/Ellipse 1").is_none(), "nothing added to the Contents");
+            let p = l.props.prop("contents/Rectangle 1/contents/Rectangle Path 1/size").expect("the rectangle stands");
+            assert_eq!(p.value.as_vec2(), [640.0, 360.0]);
+        }
+        assert!(app.ui.status.is_empty(), "{}", app.ui.status);
+    }
+
+    /// The shape tools' geometry defaults (#1072): the Rounded Rectangle tool's Roundness is a
+    /// fixed 20, the Polygon tool a 5-point polygon, the Star tool a 5-point star whose Inner
+    /// Radius is a quarter of its Outer Radius.
+    #[test]
+    fn double_click_shape_tool_geometry_defaults() {
+        let mut s = effectcraft_engine::Session::default();
+        s.execute("comp.new", json!({"width": 640, "height": 360, "duration": 2})).unwrap();
+        let mut app = EffectcraftApp::new(s);
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &app.tokens, crate::i18n::language(&app));
+        frame(&mut app, &ctx, 0.0, vec![]);
+        frame(&mut app, &ctx, 0.1, vec![]);
+        let pointer = |pos, pressed| egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed, modifiers: Default::default() };
+        let double_click = |app: &mut EffectcraftApp, ctx: &egui::Context, t: f64, id: &str| {
+            let e = app.auto.elements.iter().find(|w| w.id == id).unwrap_or_else(|| panic!("no {id}"));
+            let at = egui::pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+            frame(app, ctx, t, vec![egui::Event::PointerMoved(at), pointer(at, true), pointer(at, false), pointer(at, true), pointer(at, false)]);
+        };
+        // Each shape on its own layer: deselect so the next double-click makes a new one.
+        let deselected = |app: &mut EffectcraftApp, ctx: &egui::Context, t: f64| {
+            app.session.execute("edit.deselectAll", json!({})).unwrap();
+            frame(app, ctx, t, vec![]);
+        };
+        // The Rounded Rectangle: Roundness 20, filling the comp.
+        app.ui.slot_tools[8] = Tool::RoundedRect;
+        frame(&mut app, &ctx, 1.0, vec![]);
+        double_click(&mut app, &ctx, 1.1, "tools.RoundedRect");
+        {
+            let comp = app.session.active_comp().unwrap();
+            let g = comp.layers[0].props.group("contents/Rectangle 1/contents/Rectangle Path 1").expect("Rectangle Path 1");
+            assert_eq!(g.prop("roundness").expect("roundness").value.as_f64(), 20.0, "a fixed roundness");
+            assert_eq!(g.prop("size").expect("size").value.as_vec2(), [640.0, 360.0]);
+        }
+        // The Star: 5 points, Outer Radius half the comp height, Inner Radius a quarter.
+        deselected(&mut app, &ctx, 2.0);
+        app.ui.slot_tools[8] = Tool::Star;
+        frame(&mut app, &ctx, 2.05, vec![]);
+        double_click(&mut app, &ctx, 2.1, "tools.Star");
+        {
+            let comp = app.session.active_comp().unwrap();
+            let g = comp.layers[0].props.group("contents/Polystar 1/contents/Polystar Path 1").expect("Polystar Path 1");
+            assert_eq!(g.prop("type").expect("type").value.as_enum(), 0, "Star");
+            assert_eq!(g.prop("points").expect("points").value.as_f64(), 5.0, "5 points");
+            assert_eq!(g.prop("outerRadius").expect("outer").value.as_f64(), 180.0, "half the comp height");
+            assert_eq!(g.prop("innerRadius").expect("inner").value.as_f64(), 90.0, "a quarter of the comp height");
+        }
+        // The Polygon: 5 points, Outer Radius half the comp height, no inner radius.
+        deselected(&mut app, &ctx, 3.0);
+        app.ui.slot_tools[8] = Tool::Polygon;
+        frame(&mut app, &ctx, 3.05, vec![]);
+        double_click(&mut app, &ctx, 3.1, "tools.Polygon");
+        {
+            let comp = app.session.active_comp().unwrap();
+            let g = comp.layers[0].props.group("contents/Polystar 1/contents/Polystar Path 1").expect("Polystar Path 1");
+            assert_eq!(g.prop("type").expect("type").value.as_enum(), 1, "Polygon");
+            assert_eq!(g.prop("points").expect("points").value.as_f64(), 5.0, "5 points");
+            assert_eq!(g.prop("outerRadius").expect("outer").value.as_f64(), 180.0, "half the comp height");
+            assert!(g.prop("innerRadius").is_none(), "a polygon has no inner radius");
+        }
+        assert!(app.ui.status.is_empty(), "{}", app.ui.status);
+    }
+
+    /// A double-clicked shape is painted with the Tools bar's Fill and Stroke (#1072): the
+    /// colours and stroke width the shape tool is set to — and no outline at all when the tool
+    /// has its Stroke off.
+    #[test]
+    fn double_click_paints_with_the_shape_tools_fill_and_stroke() {
+        let mut s = effectcraft_engine::Session::default();
+        s.execute("comp.new", json!({"width": 640, "height": 360, "duration": 2})).unwrap();
+        let mut app = EffectcraftApp::new(s);
+        let ctx = egui::Context::default();
+        crate::theme::install(&ctx, &app.tokens, crate::i18n::language(&app));
+        frame(&mut app, &ctx, 0.0, vec![]);
+        frame(&mut app, &ctx, 0.1, vec![]);
+        let pointer = |pos, pressed| egui::Event::PointerButton { pos, button: egui::PointerButton::Primary, pressed, modifiers: Default::default() };
+        let double_click = |app: &mut EffectcraftApp, ctx: &egui::Context, t: f64, id: &str| {
+            let e = app.auto.elements.iter().find(|w| w.id == id).unwrap_or_else(|| panic!("no {id}"));
+            let at = egui::pos2(e.rect[0] + e.rect[2] / 2.0, e.rect[1] + e.rect[3] / 2.0);
+            frame(app, ctx, t, vec![egui::Event::PointerMoved(at), pointer(at, true), pointer(at, false), pointer(at, true), pointer(at, false)]);
+        };
+        // The tool's own Fill and Stroke go onto the created shape.
+        app.session.state.shape_tool.fill.color = [1.0, 0.0, 0.0];
+        app.session.state.shape_tool.stroke.color = [0.0, 1.0, 0.0];
+        app.session.state.shape_tool.stroke_width = 5.0;
+        double_click(&mut app, &ctx, 1.0, "tools.Rectangle");
+        {
+            let comp = app.session.active_comp().unwrap();
+            let g = comp.layers[0].props.group("contents/Rectangle 1/contents").expect("the contents");
+            let fill = g.sub("fill").expect("the fill");
+            assert_eq!(fill.get("color").expect("color").value.as_color(), [1.0, 0.0, 0.0, 1.0], "the tool's Fill");
+            let stroke = g.sub("stroke").expect("the stroke");
+            assert_eq!(stroke.get("color").expect("color").value.as_color(), [0.0, 1.0, 0.0, 1.0], "the tool's Stroke");
+            assert_eq!(stroke.get("width").expect("width").value.as_f64(), 5.0, "the tool's Stroke Width");
+        }
+        // Stroke off ("Keine"): the next shape gets no outline at all, but keeps the Fill.
+        app.session.execute("shape.toolOptions", json!({"stroke": false})).unwrap();
+        app.session.execute("edit.deselectAll", json!({})).unwrap();
+        app.ui.slot_tools[8] = Tool::Ellipse;
+        frame(&mut app, &ctx, 1.05, vec![]);
+        double_click(&mut app, &ctx, 2.0, "tools.Ellipse");
+        {
+            let comp = app.session.active_comp().unwrap();
+            assert_eq!(comp.layers.len(), 2, "a new shape layer");
+            let g = comp.layers[0].props.group("contents/Ellipse 1/contents").expect("the ellipse");
+            assert!(g.sub("stroke").is_none(), "no outline when the tool's Stroke is off");
+            assert_eq!(g.sub("fill").expect("the fill").get("color").expect("color").value.as_color(), [1.0, 0.0, 0.0, 1.0]);
+        }
+        assert!(app.ui.status.is_empty(), "{}", app.ui.status);
+    }
 }
diff --git a/crates/ui-egui/src/i18n/effects.rs b/crates/ui-egui/src/i18n/effects.rs
index 816ab3576..bb7e3715a 100644
--- a/crates/ui-egui/src/i18n/effects.rs
+++ b/crates/ui-egui/src/i18n/effects.rs
@@ -150,6 +150,7 @@ const SIMPLIFIED_CHINESE: &[Row] = &[
     ("ec.3d.fog3d", "Fog 3D", "雾 3D"),
     ("ec.3d.identifier", "IDentifier", "IDentifier"),
     ("ec.3d.idmatte", "ID Matte", "ID 遮罩"),
+    ("ec.3d.instance3d", "3D Layer Instance", "3D 图层实例"),
     ("ec.audio.backwards", "Backwards", "倒放"),
     ("ec.audio.basstreble", "Bass & Treble", "低音和高音"),
     ("ec.audio.compressor", "Compressor", "压缩程序"),
@@ -779,12 +780,13 @@ const JAPANESE_CATEGORIES: &[(&str, &str)] = &[
     ("Color Correction", "カラー補正"),
     ("Distort", "ディストーション"),
     ("Expression Controls", "式制御"),
+    ("Generate", "描画"),
     ("Immersive Video", "イマーシブビデオ"),
     ("Keying", "キーイング"),
     ("Matte", "マット"),
     ("Noise & Grain", "ノイズ＆グレイン"),
     ("Obsolete", "旧バージョン"),
-    ("Paint", "描画"),
+    ("Paint", "ペイント"),
     ("Perspective", "遠近"),
     ("Simulation", "シミュレーション"),
     ("Stylize", "スタイライズ"),
@@ -808,6 +810,7 @@ const GEORGIAN: &[Row] = &[
     ("ec.3d.fog3d", "Fog 3D", "3D ნისლი"),
     ("ec.3d.identifier", "IDentifier", "IDentifier"),
     ("ec.3d.idmatte", "ID Matte", "ID მატი"),
+    ("ec.3d.instance3d", "3D Layer Instance", "3D Layer Instance"),
     ("ec.audio.backwards", "Backwards", "უკუღმა"),
     ("ec.audio.basstreble", "Bass & Treble", "ბასი და ტრებლი"),
     ("ec.audio.compressor", "Compressor", "კომპრესორი"),
@@ -1290,3 +1293,21 @@ mod tests {
         assert!(!matches("ec.blur.gaussian", "Gaussian Blur", "高斯"));
     }
 }
+
+#[cfg(test)]
+mod japanese_category_tests {
+    use super::*;
+    use std::collections::HashMap;
+
+    /// Two categories drawing the same Japanese name would make the Effect menu show one name twice and
+    /// leave the user unable to tell them apart. `描画` was both `Generate` and `Paint` before #2583.
+    #[test]
+    fn no_two_categories_share_a_japanese_name() {
+        let mut seen: HashMap<&str, &str> = HashMap::new();
+        for (english, japanese) in JAPANESE_CATEGORIES {
+            if let Some(other) = seen.insert(japanese, english) {
+                panic!("`{english}` and `{other}` both draw as `{japanese}`");
+            }
+        }
+    }
+}
diff --git a/crates/ui-egui/src/i18n/ui.rs b/crates/ui-egui/src/i18n/ui.rs
index f5a56966c..ea0fabca2 100644
--- a/crates/ui-egui/src/i18n/ui.rs
+++ b/crates/ui-egui/src/i18n/ui.rs
@@ -475,6 +475,7 @@ const JAPANESE: &[(&str, &str)] = &[
     ("Overlay", "オーバーレイ"),
     ("Parameter Name:", "パラメーター名:"),
     ("Parent pick whip: drag onto a layer", "親ピックウィップ：レイヤー上にドラッグ"),
+    ("Track Matte pick whip: drag onto a layer", "トラックマットピックウィップ：レイヤー上にドラッグ"),
     ("Pixel Aspect Ratio:", "ピクセル縦横比:"),
     ("Play/Stop", "再生/停止"),
     ("Playing on Video Preview", "ビデオプレビューで再生中"),
@@ -1513,6 +1514,7 @@ const SIMPLIFIED_CHINESE: &[(&str, &str)] = &[
     ("Overlay", "叠加"),
     ("Parameter Name:", "参数名称："),
     ("Parent pick whip: drag onto a layer", "父级拾取器：拖到图层上"),
+    ("Track Matte pick whip: drag onto a layer", "轨道遮罩拾取器：拖到图层上"),
     ("Pixel Aspect Ratio:", "像素长宽比："),
     ("Play/Stop", "播放/停止"),
     ("Playing on Video Preview", "在视频预览中播放"),
@@ -2257,6 +2259,48 @@ const SIMPLIFIED_CHINESE: &[(&str, &str)] = &[
     ("Blend Mode", "混合模式"),
     ("Show mesh", "显示网格"),
     ("Record Options...", "记录选项..."),
+    ("Selection Tool", "选择工具"),
+    ("Hand Tool", "抓手工具"),
+    ("Zoom Tool", "缩放工具"),
+    ("Orbit Around Cursor Tool", "绕行摄像机工具"),
+    ("Pan Under Cursor Tool", "平移摄像机工具"),
+    ("Dolly Towards Cursor Tool", "推拉摄像机工具"),
+    ("Rotation Tool", "旋转工具"),
+    ("Pan Behind (Anchor Point) Tool", "向后平移工具"),
+    ("Rectangle Tool", "矩形工具"),
+    ("Rounded Rectangle Tool", "圆角矩形工具"),
+    ("Ellipse Tool", "椭圆工具"),
+    ("Polygon Tool", "多边形工具"),
+    ("Star Tool", "星形工具"),
+    ("Pen Tool", "钢笔工具"),
+    ("Add Vertex Tool", "添加顶点工具"),
+    ("Delete Vertex Tool", "删除顶点工具"),
+    ("Convert Vertex Tool", "转换顶点工具"),
+    ("Mask Feather Tool", "蒙版羽化工具"),
+    ("Horizontal Type Tool", "横排文字工具"),
+    ("Vertical Type Tool", "直排文字工具"),
+    ("Brush Tool", "画笔工具"),
+    ("Clone Stamp Tool", "仿制图章工具"),
+    ("Eraser Tool", "橡皮擦工具"),
+    ("Roto Brush Tool", "Roto 笔刷工具"),
+    ("Refine Edge Tool", "调整边缘工具"),
+    ("Object Matte Tool", "对象遮罩工具"),
+    ("Puppet Position Pin Tool", "人偶位置控点工具"),
+    ("Puppet Starch Pin Tool", "人偶扑粉控点工具"),
+    ("Puppet Bend Pin Tool", "人偶弯曲控点工具"),
+    ("Puppet Advanced Pin Tool", "人偶高级控点工具"),
+    ("Puppet Overlap Pin Tool", "人偶重叠控点工具"),
+    ("Shortcut", "快捷键"),
+    ("Range", "范围"),
+    ("Play From", "从以下位置播放"),
+    ("Resolution", "分辨率"),
+    ("Overlays", "叠加"),
+    ("Layer Controls", "图层控制"),
+    ("Loop", "循环"),
+    ("Cache Before Playback", "播放前缓存"),
+    ("Pre-roll", "预卷"),
+    ("Post-roll", "后卷"),
+    ("If caching, play cached frames", "缓存时播放已缓存帧"),
 ];
 
 const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
@@ -2556,6 +2600,7 @@ const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
     ("Overlay", "疊加"),
     ("Parameter Name:", "參數名稱："),
     ("Parent pick whip: drag onto a layer", "上層拾取線：拖到圖層上"),
+    ("Track Matte pick whip: drag onto a layer", "軌道遮罩拾取線：拖到圖層上"),
     ("Pixel Aspect Ratio:", "像素長寬比例："),
     ("Play/Stop", "播放/停止"),
     ("Playing on Video Preview", "在視訊預覽中播放"),
@@ -3094,7 +3139,6 @@ const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
     ("Create Nulls From Paths", "從路徑建立空物件"),
     ("VR Comp Editor", "VR 合成編輯器"),
     ("Media Duration", "媒體持續時間"),
-    ("Frame Rate", "幀率"),
     ("File Path", "檔案路徑"),
     ("Interpret Footage", "解譯素材"),
     ("Create a new Folder", "新增資料夾"),
@@ -3246,6 +3290,49 @@ const TRADITIONAL_CHINESE: &[(&str, &str)] = &[
     ("Blend Mode", "混合模式"),
     ("Show mesh", "顯示網格"),
     ("Record Options...", "記錄選項..."),
+    ("Selection Tool", "選取工具"),
+    ("Hand Tool", "手形工具"),
+    ("Zoom Tool", "縮放工具"),
+    ("Orbit Around Cursor Tool", "繞行攝影機工具"),
+    ("Pan Under Cursor Tool", "平移攝影機工具"),
+    ("Dolly Towards Cursor Tool", "推拉攝影機工具"),
+    ("Rotation Tool", "旋轉工具"),
+    ("Pan Behind (Anchor Point) Tool", "向後平移工具"),
+    ("Rectangle Tool", "矩形工具"),
+    ("Rounded Rectangle Tool", "圓角矩形工具"),
+    ("Ellipse Tool", "橢圓工具"),
+    ("Polygon Tool", "多邊形工具"),
+    ("Star Tool", "星形工具"),
+    ("Pen Tool", "筆型工具"),
+    ("Add Vertex Tool", "添加頂點工具"),
+    ("Delete Vertex Tool", "刪除頂點工具"),
+    ("Convert Vertex Tool", "轉換頂點工具"),
+    ("Mask Feather Tool", "遮色片羽化工具"),
+    ("Horizontal Type Tool", "橫排文字工具"),
+    ("Vertical Type Tool", "垂直文字工具"),
+    ("Brush Tool", "筆刷工具"),
+    ("Clone Stamp Tool", "仿製圖章工具"),
+    ("Eraser Tool", "橡皮擦工具"),
+    ("Roto Brush Tool", "Roto 筆刷工具"),
+    ("Refine Edge Tool", "調整邊緣工具"),
+    ("Object Matte Tool", "物件遮色片工具"),
+    ("Puppet Position Pin Tool", "人偶位置控點工具"),
+    ("Puppet Starch Pin Tool", "人偶撲粉控點工具"),
+    ("Puppet Bend Pin Tool", "人偶彎曲控點工具"),
+    ("Puppet Advanced Pin Tool", "人偶高級控點工具"),
+    ("Puppet Overlap Pin Tool", "人偶重疊控點工具"),
+    ("Shortcut", "快速鍵"),
+    ("Range", "範圍"),
+    ("Play From", "從下列位置播放"),
+    ("Frame Rate", "影格速率"),
+    ("Resolution", "解析度"),
+    ("Overlays", "覆疊"),
+    ("Layer Controls", "圖層控制"),
+    ("Loop", "循環"),
+    ("Cache Before Playback", "播放前快取"),
+    ("Pre-roll", "預卷"),
+    ("Post-roll", "後卷"),
+    ("If caching, play cached frames", "快取時播放已快取影格"),
 ];
 
 /// Ukrainian (uk): original translations of the same interface rows as the Chinese catalogs.
@@ -3558,6 +3645,7 @@ const UKRAINIAN: &[(&str, &str)] = &[
     ("Overlay", "Накладання"),
     ("Parameter Name:", "Назва параметра:"),
     ("Parent pick whip: drag onto a layer", "Зв’язування батьківського шару: перетягніть на шар"),
+    ("Track Matte pick whip: drag onto a layer", "Зв’язування трекової маски: перетягніть на шар"),
     ("Pixel Aspect Ratio:", "Пропорції пікселя:"),
     ("Playing on Video Preview", "Відтворення на відеоперегляді"),
     ("Post-Render Action: {}", "Дія після рендерингу: {}"),
@@ -4111,6 +4199,7 @@ const PORTUGUESE: &[(&str, &str)] = &[
     ("Output To:", "Saída para:"),
     ("Parameter Name:", "Nome do parâmetro:"),
     ("Parent pick whip: drag onto a layer", "Pick whip de pai: arraste até uma camada"),
+    ("Track Matte pick whip: drag onto a layer", "Pick whip de track matte: arraste até uma camada"),
     ("Pixel Aspect Ratio:", "Proporção de pixel:"),
     ("Playing on Video Preview", "Reproduzindo na visualização de vídeo"),
     ("Post-Render Action: {}", "Ação pós-renderização: {}"),
@@ -4869,6 +4958,7 @@ const CZECH: &[(&str, &str)] = &[
     ("Overlay", "Překrytí"),
     ("Parameter Name:", "Název parametru:"),
     ("Parent pick whip: drag onto a layer", "Propojovací nástroj nadřazené vrstvy: přetáhněte na vrstvu"),
+    ("Track Matte pick whip: drag onto a layer", "Propojovací nástroj masky stopy: přetáhněte na vrstvu"),
     ("Pixel Aspect Ratio:", "Poměr stran pixelů:"),
     ("Playing on Video Preview", "Přehrávání ve videonáhledu"),
     ("Post-Render Action: {}", "Akce po vykreslení: {}"),
@@ -5432,6 +5522,7 @@ const SPANISH: &[(&str, &str)] = &[
     ("Overlay", "Superposición"),
     ("Parameter Name:", "Nombre del parámetro:"),
     ("Parent pick whip: drag onto a layer", "Selector de capa padre: arrastra hasta una capa"),
+    ("Track Matte pick whip: drag onto a layer", "Selector de mate de seguimiento: arrastra hasta una capa"),
     ("Pixel Aspect Ratio:", "Relación de aspecto de píxel:"),
     ("Playing on Video Preview", "Reproduciendo en la previsualización de vídeo"),
     ("Post-Render Action: {}", "Acción posterior al procesamiento: {}"),
@@ -6657,6 +6748,7 @@ mod tests {
         ("menus/frontend.rs", include_str!("../menus/frontend.rs")),
         ("menus/invoke.rs", include_str!("../menus/invoke.rs")),
         ("menus/shortcuts.rs", include_str!("../menus/shortcuts.rs")),
+        ("state.rs", include_str!("../state.rs")),
         ("prefs_live.rs", include_str!("../prefs_live.rs")),
         ("widgets.rs", include_str!("../widgets.rs")),
         ("panels/anim_tools.rs", include_str!("../panels/anim_tools.rs")),
@@ -6736,6 +6828,55 @@ mod tests {
         rows.iter().find(|(source, _)| *source == en).map_or(en, |(_, translated)| *translated)
     }
 
+    #[test]
+    fn the_toolbar_asks_the_catalog_for_the_tool_names() {
+        let header = include_str!("../header.rs");
+        for call in ["crate::i18n::tr(tool.label())", "crate::i18n::tr(cur.label())"] {
+            assert!(header.contains(call), "header.rs no longer draws {call}");
+        }
+        assert!(
+            header.contains("app.auto.add(&format!(\"tools.select.{tool:?}\"), row.rect, tool.label())"),
+            "the automation label must stay the English tool name"
+        );
+    }
+
+    #[test]
+    fn the_preview_panel_labels_are_translated() {
+        // The Preview panel draws these from a local closure, a check table and a roll tuple, none of
+        // which the call-shape scan sees; they had no rows at all.
+        for key in [
+            "Shortcut",
+            "Range",
+            "Play From",
+            "Frame Rate",
+            "Resolution",
+            "Overlays",
+            "Layer Controls",
+            "Loop",
+            "Cache Before Playback",
+            "Pre-roll",
+            "Post-roll",
+            "If caching, play cached frames",
+        ] {
+            for (name, table) in [("Simplified", SIMPLIFIED_CHINESE), ("Traditional", TRADITIONAL_CHINESE)] {
+                let value = table.iter().find(|(k, _)| *k == key).map(|(_, v)| *v);
+                assert!(value.is_some_and(|v| !v.is_empty()), "{key} has no {name} row");
+            }
+        }
+        // A row is not a translation until the panel asks for it: the labels drawn one by one carry
+        // `tr(..)`, and the table and the roll tuple wrap the text they read at the call.
+        let source = include_str!("../panels/misc.rs");
+        for literal in ["Shortcut", "Range", "Play From", "Frame Rate", "Resolution", "Full Screen", "If caching, play cached frames"] {
+            assert!(source.contains(&format!("tr(\"{literal}\")")), "{literal} is drawn without asking the catalog");
+        }
+        for call in ["check_row(app, ui, &p, pos2(cx, cy), key, tr(text), on)", "Align2::LEFT_CENTER, tr(text),"] {
+            assert!(source.contains(call), "{call} no longer asks the catalog");
+        }
+        for table in ["\"Overlays\"", "\"Layer Controls\"", "\"Loop\"", "\"Cache Before Playback\"", "\"Pre-roll\"", "\"Post-roll\""] {
+            assert!(source.contains(table), "{table} is not in the panel");
+        }
+    }
+
     /// A row that translates nothing, repeats a source string, or changes the number of values the
     /// English source carries is a bug in the catalog itself.
     #[test]
diff --git a/crates/ui-egui/src/icons.rs b/crates/ui-egui/src/icons.rs
index 949ea3771..385a6b1ca 100644
--- a/crates/ui-egui/src/icons.rs
+++ b/crates/ui-egui/src/icons.rs
@@ -48,6 +48,8 @@ pub enum Icon {
     Speaker,
     Solo,
     Lock,
+    /// An open padlock: the shackle lifted clear of the body on the right.
+    LockOpen,
     Shy,
     Collapse,
     Quality,
@@ -402,6 +404,12 @@ pub fn paint(painter: &Painter, rect: Rect, icon: Icon, color: Color32) {
             pen.arc(8.0, 7.0, 3.0, 180.0, 360.0);
             pen.dot(8.0, 10.5, 1.0);
         }
+        LockOpen => {
+            pen.rect(3.5, 7.0, 12.5, 14.0);
+            pen.arc(8.0, 4.0, 3.0, 180.0, 360.0);
+            pen.line(&[(5.0, 4.0), (5.0, 7.0)]);
+            pen.dot(8.0, 10.5, 1.0);
+        }
         Shy => {
             pen.circle(8.0, 8.0, 5.8);
             pen.dot(6.0, 7.0, 0.8);
diff --git a/crates/ui-egui/src/menus/entries.rs b/crates/ui-egui/src/menus/entries.rs
index 8fee44a72..d7b5d56ca 100644
--- a/crates/ui-egui/src/menus/entries.rs
+++ b/crates/ui-egui/src/menus/entries.rs
@@ -119,7 +119,8 @@ pub(crate) fn entry_enabled(app: &EffectcraftApp, e: &MenuEntry) -> bool {
         }
     }
     if e.command == "edit.clear" && app.ui.focused == PanelKind::Project {
-        return app.session.is_enabled("project.delete");
+        // An open text edit stands down: Clear must not delete the comp being typed into (#2227).
+        return app.session.state.text_edit.is_none() && app.session.is_enabled("project.delete");
     }
     if e.command == "edit.clear" && app.ui.focused == PanelKind::RenderQueue {
         return !app.session.is_rendering() && !app.session.project.render_queue.is_empty();
diff --git a/crates/ui-egui/src/menus/frontend.rs b/crates/ui-egui/src/menus/frontend.rs
index a3f95ee1c..5d65ffb8f 100644
--- a/crates/ui-egui/src/menus/frontend.rs
+++ b/crates/ui-egui/src/menus/frontend.rs
@@ -488,7 +488,15 @@ pub fn frontend(app: &mut EffectcraftApp, ctx: &egui::Context, id: &str, p: Valu
             app.ui.home_templates = true;
             Value::Null
         }
-        "effect.manage" | "anim.browsePresets" => {
+        "effect.manage" => {
+            app.show_panel(PanelKind::EffectsPresets);
+            Value::Null
+        }
+        "anim.browsePresets" => {
+            app.ui.effects_search.clear();
+            app.ui.effects_view.presets = true;
+            app.ui.effects_open.insert("presets".into());
+            ctx.data_mut(|data| data.insert_temp(egui::Id::unique(crate::panels::effects_presets::REVEAL_PRESETS_ID), true));
             app.show_panel(PanelKind::EffectsPresets);
             Value::Null
         }
diff --git a/crates/ui-egui/src/menus/invoke.rs b/crates/ui-egui/src/menus/invoke.rs
index b266623f3..23065067f 100644
--- a/crates/ui-egui/src/menus/invoke.rs
+++ b/crates/ui-egui/src/menus/invoke.rs
@@ -151,7 +151,16 @@ fn vertex_delta(app: &EffectcraftApp, layer: effectcraft_engine::project::LayerI
     let s = &app.session;
     let (Some(cid), Some(comp)) = (s.active_comp_id(), s.active_comp()) else { return d };
     let Some(l) = comp.layer(layer) else { return d };
-    let ectx = effectcraft_engine::render::EvalCtx { project: &s.project, comp_id: cid, comp, time: s.time(), expr: s.expr.as_deref(), footage: None };
+    let ectx = effectcraft_engine::render::EvalCtx {
+        project: &s.project,
+        comp_id: cid,
+        comp,
+        time: s.time(),
+        expr: s.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let (l2c, _) = crate::panels::viewer::l2c(&ectx, l);
     l2c.inverse().map_or(d, |inv| {
         let v = inv.apply_vec(vec2(d[0], d[1]));
@@ -223,8 +232,13 @@ pub fn invoke(app: &mut EffectcraftApp, ctx: &egui::Context, id: &str, params: V
             return run_engine(app, ctx, "edit.pasteSvg", json!({"svg": svg}));
         }
     }
-    // Clear follows panel focus, including the Edit menu and keyboard shortcut.
+    // Clear follows panel focus, including the Edit menu and keyboard shortcut. An open text
+    // edit stands down: the user is working in a composition, and the Project-panel redirect
+    // would delete it without asking when nothing uses it (#2227).
     if id == "edit.clear" && params.as_object().is_some_and(|p| p.is_empty()) && app.ui.focused == PanelKind::Project {
+        if app.session.state.text_edit.is_some() {
+            return Ok(Value::Null);
+        }
         // Through `invoke`, so deleting items that compositions use still asks first (M3.16).
         return invoke(app, ctx, "project.delete", json!({}));
     }
diff --git a/crates/ui-egui/src/native_menu.rs b/crates/ui-egui/src/native_menu.rs
index 1ca573e8e..85d0fb193 100644
--- a/crates/ui-egui/src/native_menu.rs
+++ b/crates/ui-egui/src/native_menu.rs
@@ -131,18 +131,28 @@ impl NativeMenu {
 /// otherwise follows the project clipboard and would be greyed out with nothing copied there,
 /// while the field can paste.
 pub fn build_now(app: &EffectcraftApp, ctx: &egui::Context) -> NativeMenu {
-    fn enable(nodes: &mut [NativeNode]) {
+    fn enable(app: &EffectcraftApp, nodes: &mut [NativeNode]) {
         for node in nodes {
             match node {
-                NativeNode::Item(item) if edits_text(&item.command) => item.enabled = true,
-                NativeNode::Submenu { children, .. } => enable(children),
+                NativeNode::Item(item) if edits_text(&item.command) => {
+                    item.enabled = true;
+                    let source = match item.command.as_str() {
+                        "edit.undo" => Some("Undo"),
+                        "edit.redo" => Some("Redo"),
+                        _ => None,
+                    };
+                    if let Some(source) = source {
+                        item.label = crate::i18n::label(app, &item.command, source).into();
+                    }
+                }
+                NativeNode::Submenu { children, .. } => enable(app, children),
                 _ => {}
             }
         }
     }
     let mut menu = build(app);
     if text_field_window(ctx).is_some() {
-        enable(&mut menu.menus);
+        enable(app, &mut menu.menus);
     }
     menu
 }
@@ -742,4 +752,45 @@ mod tests {
         assert!(edits_text("edit.copy") && edits_text("edit.paste"));
         assert!(!edits_text("layer.newNull"));
     }
+    /// #2459: while a text field has the keyboard the Edit menu's Undo and Redo act on the field and
+    /// read plain "Undo" / "Redo"; the project history labels come back once focus leaves.
+    #[test]
+    fn a_focused_text_field_gets_plain_undo_and_redo_labels() {
+        fn label(menu: &NativeMenu, id: &str) -> String {
+            menu.items().into_iter().find(|i| i.command == id).map(|i| i.label.to_string()).unwrap_or_default()
+        }
+        for (language, undo, redo) in [("en", "Undo", "Redo"), ("ja", "取り消し", "やり直し")] {
+            let mut app = app();
+            app.session.execute("prefs.set", json!({"key": "general.language", "value": language})).unwrap();
+            app.session.execute("layer.newNull", json!({})).unwrap();
+            app.session.execute("layer.newNull", json!({})).unwrap();
+            app.session.execute("edit.undo", json!({})).unwrap();
+            let ctx = egui::Context::default();
+            let history = label(&build_now(&app, &ctx), "edit.undo");
+            let redo_history = label(&build_now(&app, &ctx), "edit.redo");
+            assert!(history.starts_with(undo) && history != undo, "{history}");
+            assert!(redo_history.starts_with(redo) && redo_history != redo, "{redo_history}");
+            let mut text = String::new();
+            let mut id = None;
+            for _ in 0..2 {
+                let mut out = ctx.run_ui(egui::RawInput::default(), |ui| {
+                    let r = ui.text_edit_singleline(&mut text);
+                    r.request_focus();
+                    id = Some(r.id);
+                });
+                out.textures_delta.clear();
+            }
+            assert!(text_field_window(&ctx).is_some());
+            let typing = build_now(&app, &ctx);
+            assert_eq!(label(&typing, "edit.undo"), undo);
+            assert_eq!(label(&typing, "edit.redo"), redo);
+            assert!(typing.items().into_iter().any(|i| i.command == "edit.undo" && i.enabled));
+            assert!(typing.items().into_iter().any(|i| i.command == "edit.redo" && i.enabled));
+            ctx.memory_mut(|m| m.surrender_focus(id.unwrap_or(egui::Id::NULL)));
+            assert!(text_field_window(&ctx).is_none());
+            let after = build_now(&app, &ctx);
+            assert_eq!(label(&after, "edit.undo"), history);
+            assert_eq!(label(&after, "edit.redo"), redo_history);
+        }
+    }
 }
diff --git a/crates/ui-egui/src/panels.rs b/crates/ui-egui/src/panels.rs
index 9a8fd2a54..d386d9784 100644
--- a/crates/ui-egui/src/panels.rs
+++ b/crates/ui-egui/src/panels.rs
@@ -175,6 +175,56 @@ pub(crate) fn space_hand(ctx: &egui::Context) -> bool {
     ctx.input(|i| i.key_down(egui::Key::Space)) && !ctx.egui_wants_keyboard_input()
 }
 
+/// What a scroll gesture over a viewer (Composition, Layer) does this frame.
+pub(crate) struct ViewerScroll {
+    /// Points to pan by: a two-finger trackpad scroll.
+    pub pan: egui::Vec2,
+    /// Factor to zoom by around the pointer: a pinch, Ctrl/Cmd+scroll, a mouse wheel, or
+    /// Alt + a trackpad scroll.
+    pub zoom: f32,
+}
+
+/// Splits the frame's scroll input into a viewer pan and a zoom: a mouse wheel zooms and a
+/// trackpad's two-finger scroll pans.
+///
+/// Where the platform names the device (`MouseWheelSource`, macOS), that decides. Elsewhere a
+/// wheel scrolls in lines, but in a browser and with some high-resolution wheels it scrolls in
+/// points like a trackpad does, so the unit alone doesn't tell them apart. A scroll in points is
+/// a trackpad's once it has shown what a wheel can't do: a touch phase, movement on both axes at
+/// once, or a pinch. That holds until a wheel scrolls in lines. Until then the vertical part
+/// zooms; the horizontal part always pans.
+pub(crate) fn viewer_scroll(ctx: &egui::Context) -> ViewerScroll {
+    let id = egui::Id::unique("viewer-scroll-trackpad");
+    // The scroll is smoothed over the frames after its event, so the device is remembered.
+    let was: bool = ctx.data(|d| d.get_temp(id)).unwrap_or(false);
+    let trackpad = ctx.input(|i| {
+        i.events.iter().fold(was, |t, e| match e {
+            egui::Event::MouseWheel { source: egui::MouseWheelSource::Trackpad | egui::MouseWheelSource::Momentum, .. } => true,
+            egui::Event::MouseWheel { source: egui::MouseWheelSource::Wheel, .. } => false,
+            egui::Event::MouseWheel { unit: egui::MouseWheelUnit::Point, delta, phase, modifiers, .. } => {
+                // Shift turns a wheel's scroll sideways, which is still one axis.
+                t || *phase == egui::TouchPhase::Start || (delta.x != 0.0 && delta.y != 0.0 && !modifiers.shift)
+            }
+            egui::Event::MouseWheel { .. } => false,
+            egui::Event::Zoom(_) => true,
+            _ => t,
+        })
+    });
+    if trackpad != was {
+        ctx.data_mut(|d| d.insert_temp(id, trackpad));
+    }
+    let (scroll, pinch, alt) = ctx.input(|i| (i.smooth_scroll_delta, i.zoom_delta(), i.modifiers.alt));
+    let pinch = if pinch.is_finite() && pinch > 0.0 { pinch } else { 1.0 };
+    let scroll = if scroll.x.is_finite() && scroll.y.is_finite() { scroll } else { egui::Vec2::ZERO };
+    if trackpad && !alt {
+        ViewerScroll { pan: scroll, zoom: pinch }
+    } else if alt {
+        ViewerScroll { pan: egui::Vec2::ZERO, zoom: pinch * (scroll.y / 300.0).exp() }
+    } else {
+        ViewerScroll { pan: egui::vec2(scroll.x, 0.0), zoom: pinch * (scroll.y / 300.0).exp() }
+    }
+}
+
 pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: PanelKind, rect: Rect) {
     match p {
         PanelKind::Composition => viewers::show(app, ui, 0, rect),
diff --git a/crates/ui-egui/src/panels/comp_settings.rs b/crates/ui-egui/src/panels/comp_settings.rs
index 39d636666..00c87323a 100644
--- a/crates/ui-egui/src/panels/comp_settings.rs
+++ b/crates/ui-egui/src/panels/comp_settings.rs
@@ -246,36 +246,18 @@ fn matches(d: &CompDraft, w: u32, h: u32, par: f64, fps: f64) -> bool {
     w == d.width && h == d.height && (par - d.pixel_aspect).abs() < 1e-3 && (fps - d.fps).abs() < 1e-3
 }
 
-/// Draw the dialog. Returns `Some(params)` when OK is pressed, `Some(Null)` on Cancel. `custom`
-/// are the presets the user saved; saving or deleting one pushes its engine command to `cmds`.
-pub fn show(
+/// The controls of one tab.
+fn tab_body(
     ui: &mut egui::Ui,
+    tab: Tab,
     d: &mut CompDraft,
     t: &Tokens,
     auto: &mut Registry,
     custom: &[CompPreset],
     cmds: &mut Vec<(&'static str, serde_json::Value)>,
-) -> Option<serde_json::Value> {
-    let mut out = None;
-    ui.horizontal(|ui| {
-        ui.label(tr("Composition Name:"));
-        let r = ui.add(egui::TextEdit::singleline(&mut d.name).desired_width(300.0));
-        crate::widgets::focus_on_open(ui.ctx(), &r, &d.name);
-        auto.add("dialog.comp.name", r.rect, "Composition Name");
-    });
-    ui.add_space(8.0);
-    ui.horizontal(|ui| {
-        for (tab, label, key) in [(Tab::Basic, "Basic", "basic"), (Tab::Advanced, "Advanced", "advanced"), (Tab::Renderer, "3D Renderer", "renderer")] {
-            let r = ui.selectable_label(d.tab == tab, crate::i18n::tr(label));
-            auto.add(&format!("dialog.comp.tab.{key}"), r.rect, label);
-            if r.clicked() {
-                d.tab = tab;
-            }
-        }
-    });
-    ui.separator();
+) {
     let rate = FrameRate::from_f64(d.fps);
-    match d.tab {
+    match tab {
         Tab::Basic => {
             egui::Grid::new("comp-basic").num_columns(2).spacing([12.0, 9.0]).show(ui, |ui| {
                 ui.label(tr("Preset:"));
@@ -485,6 +467,54 @@ pub fn show(
             });
         }
     }
+}
+
+/// The height `tab` would take at `top`, from laying it out unseen: it follows the font, the
+/// language and the scale. Nothing it registers or changes is kept.
+fn tab_height(ui: &mut egui::Ui, tab: Tab, d: &CompDraft, t: &Tokens, custom: &[CompPreset], top: f32) -> f32 {
+    let rect = egui::Rect::from_min_size(egui::pos2(ui.max_rect().left(), top), vec2(ui.max_rect().width(), 0.0));
+    let mut child = ui.new_child(egui::UiBuilder::new().max_rect(rect).id_salt("comp-tab-measure").invisible());
+    tab_body(&mut child, tab, &mut d.clone(), t, &mut Registry::default(), custom, &mut Vec::new());
+    child.cursor().top() - top
+}
+
+/// Draw the dialog. Returns `Some(params)` when OK is pressed, `Some(Null)` on Cancel. `custom`
+/// are the presets the user saved; saving or deleting one pushes its engine command to `cmds`.
+pub fn show(
+    ui: &mut egui::Ui,
+    d: &mut CompDraft,
+    t: &Tokens,
+    auto: &mut Registry,
+    custom: &[CompPreset],
+    cmds: &mut Vec<(&'static str, serde_json::Value)>,
+) -> Option<serde_json::Value> {
+    let mut out = None;
+    ui.horizontal(|ui| {
+        ui.label(tr("Composition Name:"));
+        let r = ui.add(egui::TextEdit::singleline(&mut d.name).desired_width(300.0));
+        crate::widgets::focus_on_open(ui.ctx(), &r, &d.name);
+        auto.add("dialog.comp.name", r.rect, "Composition Name");
+    });
+    ui.add_space(8.0);
+    ui.horizontal(|ui| {
+        for (tab, label, key) in [(Tab::Basic, "Basic", "basic"), (Tab::Advanced, "Advanced", "advanced"), (Tab::Renderer, "3D Renderer", "renderer")] {
+            let r = ui.selectable_label(d.tab == tab, tr(label));
+            auto.add(&format!("dialog.comp.tab.{key}"), r.rect, label);
+            if r.clicked() {
+                d.tab = tab;
+            }
+        }
+    });
+    ui.separator();
+    // Every tab takes the height of the tallest one, so Cancel and OK stay put between tabs.
+    let body_top = ui.cursor().top();
+    tab_body(ui, d.tab, d, t, auto, custom, cmds);
+    let shown = ui.cursor().top() - body_top;
+    let tallest = [Tab::Basic, Tab::Advanced, Tab::Renderer]
+        .into_iter()
+        .filter(|tab| *tab != d.tab)
+        .fold(shown, |h, tab| h.max(tab_height(ui, tab, d, t, custom, body_top)));
+    ui.add_space((tallest - shown).max(0.0));
     ui.add_space(14.0);
     ui.horizontal(|ui| {
         ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
diff --git a/crates/ui-egui/src/panels/effect_controls/panel.rs b/crates/ui-egui/src/panels/effect_controls/panel.rs
index 39cdee76c..12f3e0057 100644
--- a/crates/ui-egui/src/panels/effect_controls/panel.rs
+++ b/crates/ui-egui/src/panels/effect_controls/panel.rs
@@ -166,7 +166,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let comp_name = app.session.project.item(cid).map(|i| i.name.clone()).unwrap_or_default();
     let snap_project = app.session.project.clone();
     let snap_expr = app.session.expr.clone();
-    let ectx = EvalCtx { project: &snap_project, comp_id: cid, comp: &comp, time: app.session.time(), expr: snap_expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &snap_project,
+        comp_id: cid,
+        comp: &comp,
+        time: app.session.time(),
+        expr: snap_expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let hdr = Rect::from_min_size(rect.min, vec2(rect.width(), 24.0));
     p.text(pos2(hdr.min.x + 10.0, hdr.center().y), Align2::LEFT_CENTER, format!("{} • {}", comp_name, layer.name), Tokens::ui(11.5), t.text_dim);
     p.line_segment([hdr.left_bottom(), hdr.right_bottom()], Stroke::new(1.0, t.separator));
diff --git a/crates/ui-egui/src/panels/effect_controls/rows.rs b/crates/ui-egui/src/panels/effect_controls/rows.rs
index 05fea44c9..249c8462b 100644
--- a/crates/ui-egui/src/panels/effect_controls/rows.rs
+++ b/crates/ui-egui/src/panels/effect_controls/rows.rs
@@ -88,6 +88,11 @@ struct PropCx<'a> {
 }
 
 impl PropCx<'_> {
+    /// The tokens of the value fields: red while an expression drives the parameter (#1306).
+    fn value_tokens(&self) -> Tokens {
+        self.t.for_value(self.prop.has_expression())
+    }
+
     fn set(&self, actions: &mut Actions, v: serde_json::Value) {
         let (layer, uid, merge, scrub) = (self.layer, self.uid, format!("ec-{}", self.uid), self.scrub);
         actions.push(("prop.set".into(), json!({"layer": layer.id.0, "prop": uid, "value": v, "merge": merge, "selected": true, "offset": scrub})))
@@ -243,8 +248,8 @@ fn value_angle(app: &mut EffectcraftApp, ui: &mut egui::Ui, cx: &PropCx, value:
     let Value::Scalar(v) = value else {
         return;
     };
-    let PropCx { t, uid, cy, vx, prop, .. } = *cx;
-    let (rr, dr, nv) = fw::angle_field(ui, pos2(vx, cy - 9.0), egui::Id::unique(("ec-v", uid)), *v, 1, &t);
+    let PropCx { uid, cy, vx, prop, .. } = *cx;
+    let (rr, dr, nv) = fw::angle_field(ui, pos2(vx, cy - 9.0), egui::Id::unique(("ec-v", uid)), *v, 1, &cx.value_tokens());
     app.auto.add(&format!("effectControls.prop.{uid}.value"), rr.union(dr), &fw::format_angle(*v, 1));
     app.auto.add(&format!("effectControls.prop.{uid}.revolutions"), rr, &prop.name);
     if let Some(nv) = nv {
@@ -257,7 +262,7 @@ fn value_scalar(app: &mut EffectcraftApp, ui: &mut egui::Ui, cx: &PropCx, value:
     let Value::Scalar(v) = value else {
         return;
     };
-    let PropCx { t, uid, cy, vx, prop, .. } = *cx;
+    let PropCx { uid, cy, vx, prop, .. } = *cx;
     let (min, max, dec) = match &prop.ui {
         ParamUi::Slider { min, max, decimals, .. } => (*min, *max, *decimals as usize),
         _ => (-1e9, 1e9, 1),
@@ -273,7 +278,7 @@ fn value_scalar(app: &mut EffectcraftApp, ui: &mut egui::Ui, cx: &PropCx, value:
         egui::Id::unique(("ec-v", uid)),
         *v,
         &widgets::HotSpec { speed, range: (min, max), decimals: dec.max(if dec == 0 { 0 } else { 1 }), suffix },
-        &t,
+        &cx.value_tokens(),
     );
     app.auto.add(&format!("effectControls.prop.{uid}.value"), vr, &prop.name);
     if let Some(nv) = nv {
@@ -290,6 +295,7 @@ fn value_vector(app: &mut EffectcraftApp, ui: &mut egui::Ui, cx: &PropCx, value:
     let PropCx { t, uid, cy, vx, layer, prop, .. } = *cx;
     let c = value.components();
     let n = shown_dims(layer, prop, value);
+    let vt = cx.value_tokens();
     let mut x = vx;
     if matches!(prop.ui, ParamUi::Point | ParamUi::Point3) {
         let cr = Rect::from_center_size(pos2(x + 8.0, cy), vec2(18.0, 18.0));
@@ -310,7 +316,7 @@ fn value_vector(app: &mut EffectcraftApp, ui: &mut egui::Ui, cx: &PropCx, value:
             egui::Id::unique(("ec-v", uid, d)),
             c[d],
             &widgets::HotSpec { speed: 1.0, range: (-1e9, 1e9), decimals: 1, suffix: "" },
-            &t,
+            &vt,
         );
         app.auto.add(&format!("effectControls.prop.{uid}.value.{d}"), vr, &prop.name);
         dims.push(vr);
diff --git a/crates/ui-egui/src/panels/effects_presets.rs b/crates/ui-egui/src/panels/effects_presets.rs
index 380d1d869..44c77ec22 100644
--- a/crates/ui-egui/src/panels/effects_presets.rs
+++ b/crates/ui-egui/src/panels/effects_presets.rs
@@ -17,6 +17,7 @@ use crate::{EffectcraftApp, widgets};
 
 const ROW_H: f32 = 21.0;
 const RECENT_MAX: usize = 8;
+pub(crate) const REVEAL_PRESETS_ID: &str = "fx-reveal-presets";
 
 /// A user animation preset file.
 #[derive(Clone, Debug, PartialEq)]
@@ -157,6 +158,24 @@ fn folder_row(
     open
 }
 
+/// Number of visible rows before Animation Presets in the current panel state.
+fn rows_before_presets(favorites: usize, recent: usize, searching: bool, favorites_open: bool, recent_open: bool) -> usize {
+    let mut rows = 0usize;
+    if favorites > 0 {
+        rows = rows.saturating_add(1);
+        if searching || favorites_open {
+            rows = rows.saturating_add(favorites);
+        }
+    }
+    if !searching && recent > 0 {
+        rows = rows.saturating_add(1);
+        if recent_open {
+            rows = rows.saturating_add(recent);
+        }
+    }
+    rows
+}
+
 /// An effect row (fx icon, highlighted name, favourite star, 32 bpc badge).
 #[allow(clippy::too_many_arguments)]
 fn effect_row(
@@ -364,7 +383,7 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let view = app.ui.effects_view.clone();
     let list = Rect::from_min_max(pos2(rect.min.x, sr.max.y + 6.0), rect.max);
     let lp = p.with_clip_rect(list);
-    let scroll = widgets::PanelScroll::begin(ui, egui::Id::unique("fx-scroll"), list);
+    let mut scroll = widgets::PanelScroll::begin(ui, egui::Id::unique("fx-scroll"), list);
     let query = q.trim().to_lowercase();
     let searching = !query.is_empty();
     let mut y = list.min.y - scroll.offset;
@@ -378,6 +397,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
 
     // Favorites and Recently Used.
     let favs: Vec<_> = app.session.prefs.effects_favorites.iter().filter_map(|id| lookup(id)).filter(|e| keep(e)).collect();
+    let recent: Vec<_> = app.ui.effects_recent.iter().filter_map(|id| lookup(id)).filter(|e| keep(e)).collect();
+    let reveal_presets = ctx.data_mut(|data| data.remove_temp::<bool>(egui::Id::unique(REVEAL_PRESETS_ID))).unwrap_or(false);
+    if reveal_presets {
+        // These rows come before Animation Presets. Scroll past expanded lists so the section is
+        // visible even when Favorites or Recently Used is long.
+        let preceding_rows =
+            rows_before_presets(favs.len(), recent.len(), searching, app.ui.effects_open.contains("favorites"), app.ui.effects_open.contains("recent"));
+        scroll.offset = ROW_H * preceding_rows as f32;
+        y = list.min.y - scroll.offset;
+    }
     if !favs.is_empty() && folder_row(app, ui, &lp, list, &mut y, "favorites", "Favorites", 0.0, searching, Some(Icon::Star)) {
         let mut favs = favs;
         favs.sort_by_key(|e| e.name);
@@ -385,7 +414,6 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
             effect_row(app, ui, &lp, list, &mut y, e, 0.0, &query, "effects.favorites", &mut apply);
         }
     }
-    let recent: Vec<_> = app.ui.effects_recent.iter().filter_map(|id| lookup(id)).filter(|e| keep(e)).collect();
     if !recent.is_empty() && !searching && folder_row(app, ui, &lp, list, &mut y, "recent", "Recently Used", 0.0, false, None) {
         for e in recent {
             effect_row(app, ui, &lp, list, &mut y, e, 0.0, &query, "effects.recent", &mut apply);
diff --git a/crates/ui-egui/src/panels/expr_editor.rs b/crates/ui-egui/src/panels/expr_editor.rs
index 157288b94..6d742dc4e 100644
--- a/crates/ui-egui/src/panels/expr_editor.rs
+++ b/crates/ui-egui/src/panels/expr_editor.rs
@@ -111,6 +111,7 @@ pub const COMPLETIONS: &[&str] = &[
     "ease",
     "easeIn",
     "easeOut",
+    "bezier",
     "clamp",
     "random",
     "gaussRandom",
diff --git a/crates/ui-egui/src/panels/layer_panel.rs b/crates/ui-egui/src/panels/layer_panel.rs
index 5fb4d703c..8e4f3502f 100644
--- a/crates/ui-egui/src/panels/layer_panel.rs
+++ b/crates/ui-egui/src/panels/layer_panel.rs
@@ -104,7 +104,16 @@ fn render_tex(
     match cached {
         Some(c) if c.key == key => Some(c),
         _ => {
-            let ectx = EvalCtx { project: &app.session.project, comp_id: cid, comp, time, expr: app.session.expr.as_deref(), footage: None };
+            let ectx = EvalCtx {
+                project: &app.session.project,
+                comp_id: cid,
+                comp,
+                time,
+                expr: app.session.expr.as_deref(),
+                footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
+            };
             let mut r = Renderer::new(&app.session.project, &*app.session.footage, RenderOpts { scale, ..Default::default() });
             r.expr = app.session.expr.as_deref();
             r.cache = Some(&app.session.layer_cache);
@@ -310,13 +319,17 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     app.auto.add("layerPanel.canvas", frame, &layer.name);
     app.auto.add("layerPanel.area", area, "Layer panel");
 
-    // Navigation (as the Composition panel): the wheel / pinch zooms around the pointer with any
-    // tool; the Hand tool or Space-drag pans and the Zoom tool clicks zoom in (Alt: out).
+    // Navigation (as the Composition panel): the wheel / pinch zooms around the pointer and a
+    // two-finger trackpad scroll pans with any tool; the Hand tool or Space-drag pans and the
+    // Zoom tool clicks zoom in (Alt: out).
     let hovered = ui.rect_contains_pointer(area);
     if let Some(hp) = ui.input(|i| i.pointer.hover_pos()).filter(|_| hovered) {
-        let scroll = ui.input(|i| i.smooth_scroll_delta.y + i.zoom_delta().ln() * 300.0);
-        if scroll.is_finite() && scroll.abs() > 0.1 {
-            zoom_at(app, area, [lw, lh], hp, to_layer(hp), zoom as f32 * (scroll / 300.0).exp());
+        let scroll = super::viewer_scroll(&ctx);
+        if (scroll.zoom - 1.0).abs() > 3e-4 {
+            zoom_at(app, area, [lw, lh], hp, to_layer(hp), zoom as f32 * scroll.zoom);
+        } else if scroll.pan != egui::Vec2::ZERO {
+            app.ui.layer_zoom.get_or_insert(zoom as f32);
+            app.ui.layer_pan = [pan.x + scroll.pan.x, pan.y + scroll.pan.y];
         }
     }
     // A middle-drag pans with any tool; painting and Roto Brush strokes don't run meanwhile.
diff --git a/crates/ui-egui/src/panels/misc.rs b/crates/ui-egui/src/panels/misc.rs
index 329d754f3..32fc1e8d2 100644
--- a/crates/ui-egui/src/panels/misc.rs
+++ b/crates/ui-egui/src/panels/misc.rs
@@ -64,7 +64,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let mut yy = y + 46.0;
 
     // Shortcut.
-    label(yy, "Shortcut");
+    label(yy, tr("Shortcut"));
     let names: Vec<String> = PreviewShortcut::ALL.iter().map(|s| s.label().to_string()).collect();
     if let Some(i) = dropdown_row(
         app,
@@ -94,14 +94,14 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         let row = if i < 4 { i / 2 } else { i - 2 };
         let cx = x0 + col as f32 * 110.0 - 2.0;
         let cy = yy + row as f32 * 22.0;
-        if check_row(app, ui, &p, pos2(cx, cy), key, text, on) {
+        if check_row(app, ui, &p, pos2(cx, cy), key, tr(text), on) {
             changes.push(json!({"shortcut": current.id(), key: !on}));
         }
     }
     yy += 4.0 * 22.0 + 6.0;
 
     // Range (and the pre/post-roll of Play Around Current Time).
-    label(yy, "Range");
+    label(yy, tr("Range"));
     let ranges: Vec<String> = PreviewRange::ALL.iter().map(|r| r.label().to_string()).collect();
     let range_ids = ["workArea", "workAreaExtended", "entireDuration", "aroundCurrentTime"];
     if let Some(i) = dropdown_row(
@@ -119,7 +119,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     if o.range == PreviewRange::AroundCurrentTime {
         for (k, (key, text, v)) in [("preRoll", "Pre-roll", o.pre_roll), ("postRoll", "Post-roll", o.post_roll)].into_iter().enumerate() {
             let lx = xv + k as f32 * 100.0;
-            p.text(pos2(lx, yy), Align2::LEFT_CENTER, text, Tokens::ui(11.5), t.text_dim);
+            p.text(pos2(lx, yy), Align2::LEFT_CENTER, tr(text), Tokens::ui(11.5), t.text_dim);
             let (r, nv, _) = widgets::hot_number_at(
                 ui,
                 pos2(lx + 52.0, yy - 9.0),
@@ -137,7 +137,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     }
 
     // Play From.
-    label(yy, "Play From");
+    label(yy, tr("Play From"));
     let froms: Vec<String> = PlayFrom::ALL.iter().map(|f| f.label().to_string()).collect();
     if let Some(i) = dropdown_row(
         app,
@@ -154,7 +154,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
 
     // Frame Rate, Skip, Resolution.
     let comp_fps = app.session.active_comp().map(|c| c.frame_rate.as_f64());
-    label(yy, "Frame Rate");
+    label(yy, tr("Frame Rate"));
     const RATES: [f64; 12] = [8.0, 10.0, 12.0, 12.5, 15.0, 23.976, 24.0, 25.0, 29.97, 30.0, 50.0, 60.0];
     let auto = format!("({:.2}) Auto", comp_fps.unwrap_or(0.0));
     let mut rates = vec![auto.clone()];
@@ -183,7 +183,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         changes.push(json!({"shortcut": current.id(), "skip": nv.round() as u32}));
     }
     yy += 24.0;
-    label(yy, "Resolution");
+    label(yy, tr("Resolution"));
     let ress: Vec<String> = PreviewResolution::ALL.iter().map(|r| r.label().to_string()).collect();
     let res_ids = ["auto", "full", "half", "third", "quarter", "custom"];
     if let Some(i) = dropdown_row(
@@ -212,7 +212,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
         }
     }
     yy += 24.0;
-    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "fullScreen", "Full Screen", o.full_screen) {
+    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "fullScreen", tr("Full Screen"), o.full_screen) {
         changes.push(json!({"shortcut": current.id(), "fullScreen": !o.full_screen}));
     }
     yy += 24.0;
@@ -220,7 +220,7 @@ pub fn preview(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     // What stopping does.
     p.text(pos2(x0, yy), Align2::LEFT_CENTER, tr_args("On ({}) stop:", &[&(current.label())]), Tokens::ui(11.5), t.text_dim);
     yy += 20.0;
-    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "playCachedFrames", "If caching, play cached frames", o.play_cached_frames) {
+    if check_row(app, ui, &p, pos2(x0 - 2.0, yy), "playCachedFrames", tr("If caching, play cached frames"), o.play_cached_frames) {
         changes.push(json!({"shortcut": current.id(), "playCachedFrames": !o.play_cached_frames}));
     }
     yy += 22.0;
diff --git a/crates/ui-egui/src/panels/properties.rs b/crates/ui-egui/src/panels/properties.rs
index c35108937..a7563a6ff 100644
--- a/crates/ui-egui/src/panels/properties.rs
+++ b/crates/ui-egui/src/panels/properties.rs
@@ -70,7 +70,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     let project = app.session.project.clone();
     let expr = app.session.expr.clone();
     let now = app.session.time();
-    let ectx = EvalCtx { project: &project, comp_id: cid, comp: &comp, time: now, expr: expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &project,
+        comp_id: cid,
+        comp: &comp,
+        time: now,
+        expr: expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let x0 = rect.min.x + PAD;
     let w = rect.width() - 2.0 * PAD;
     let scroll = widgets::PanelScroll::begin(ui, egui::Id::unique("props-scroll"), rect);
@@ -200,6 +209,8 @@ fn triangle(p: &egui::Painter, c: egui::Pos2, left: bool, col: Color32) {
 #[allow(clippy::too_many_arguments)]
 fn transform_row(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter, layer: &Layer, pr: &Property, ectx: &EvalCtx, r: Rect, actions: &mut Actions) {
     let t = app.tokens;
+    // The values themselves: red while an expression drives the property (#1306).
+    let vt = t.for_value(pr.has_expression());
     let cy = r.center().y;
     let uid = pr.uid;
     let lid = layer.id.0;
@@ -276,7 +287,7 @@ fn transform_row(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter,
     match &value {
         Value::Scalar(v) if pr.name == "Rotation" || pr.name.ends_with(" Rotation") => {
             let (_, deg) = super::fx_widgets::split_angle(*v);
-            let (rr, dr, nv) = super::fx_widgets::angle_field(ui, pos2(vx, cy - 9.0), egui::Id::unique(("props-v", uid)), *v, decimals(deg), &t);
+            let (rr, dr, nv) = super::fx_widgets::angle_field(ui, pos2(vx, cy - 9.0), egui::Id::unique(("props-v", uid)), *v, decimals(deg), &vt);
             app.auto.add(&format!("{base}.value"), dr, &pr.name);
             app.auto.add(&format!("{base}.revolutions"), rr, &pr.name);
             if let Some(nv) = nv {
@@ -291,7 +302,7 @@ fn transform_row(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter,
                 egui::Id::unique(("props-v", uid)),
                 *v,
                 &widgets::HotSpec { speed: 0.5, range, decimals: decimals(*v), suffix },
-                &t,
+                &vt,
             );
             app.auto.add(&format!("{base}.value"), vr, &pr.name);
             if let Some(nv) = nv {
@@ -323,7 +334,7 @@ fn transform_row(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter,
                     egui::Id::unique(("props-v", uid, d)),
                     c[d],
                     &widgets::HotSpec { speed: 1.0, range: (-1e9, 1e9), decimals: decimals(c[d]), suffix },
-                    &t,
+                    &vt,
                 );
                 app.auto.add(&format!("{base}.value.{d}"), vr, &pr.name);
                 if let Some(nv) = nv {
diff --git a/crates/ui-egui/src/panels/roto_tool.rs b/crates/ui-egui/src/panels/roto_tool.rs
index 0d9eefe45..ca3c56ac5 100644
--- a/crates/ui-egui/src/panels/roto_tool.rs
+++ b/crates/ui-egui/src/panels/roto_tool.rs
@@ -69,7 +69,16 @@ pub fn draw_overlay(
     let ov = match cached {
         Some(c) if c.key == key => Some(c),
         _ => {
-            let ectx = EvalCtx { project: &app.session.project, comp_id: cid, comp, time, expr: app.session.expr.as_deref(), footage: None };
+            let ectx = EvalCtx {
+                project: &app.session.project,
+                comp_id: cid,
+                comp,
+                time,
+                expr: app.session.expr.as_deref(),
+                footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
+            };
             let mut r = Renderer::new(&app.session.project, &*app.session.footage, RenderOpts { scale, ..Default::default() });
             r.expr = app.session.expr.as_deref();
             r.cache = Some(&app.session.layer_cache);
diff --git a/crates/ui-egui/src/panels/text_panels.rs b/crates/ui-egui/src/panels/text_panels.rs
index 6a36fbbc9..38c93ebd4 100644
--- a/crates/ui-egui/src/panels/text_panels.rs
+++ b/crates/ui-egui/src/panels/text_panels.rs
@@ -3,7 +3,7 @@
 //! otherwise they apply to the whole selected text layer.
 
 use crate::i18n::tr;
-use effectcraft_engine::keyframe::{BaselineOption, Composer, Direction, FigureStyle, FigureWidth, Justify, Kerning, TextDoc};
+use effectcraft_engine::keyframe::{BaselineOption, Composer, Direction, FigureStyle, FigureWidth, Justify, Kerning, LineJoin, TextDoc};
 use effectcraft_engine::render::EvalCtx;
 use egui::{Align2, Rect, Sense, pos2, vec2};
 use serde_json::json;
@@ -57,7 +57,16 @@ pub fn text_target(app: &EffectcraftApp) -> Option<TextTarget> {
         .iter()
         .filter_map(|id| comp.layer(*id))
         .find(|l| matches!(l.source, effectcraft_engine::project::LayerSource::Text))?;
-    let ectx = EvalCtx { project: &app.session.project, comp_id: cid, comp, time: app.session.time(), expr: app.session.expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &app.session.project,
+        comp_id: cid,
+        comp,
+        time: app.session.time(),
+        expr: app.session.expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     effectcraft_engine::render::text::source_text(&ectx, layer).map(|d| TextTarget { layer: layer.id.0, doc: d, range: None })
 }
 
@@ -182,6 +191,20 @@ fn stroke_order_field(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: Grid, doc:
     }
 }
 
+/// Line Join of the stroke: Miter / Round / Bevel (grid row 5, under the stroke width).
+fn line_join_field(app: &mut EffectcraftApp, ui: &mut egui::Ui, p: &egui::Painter, g: Grid, doc: &TextDoc, actions: &mut Vec<serde_json::Value>) {
+    let Grid { x0, y, w, enabled } = g;
+    let bw = (w - 2.0 * 4.0) / 3.0;
+    for (i, (key, label, join)) in
+        [("miter", "Miter", LineJoin::Miter), ("round", "Round", LineJoin::Round), ("bevel", "Bevel", LineJoin::Bevel)].into_iter().enumerate()
+    {
+        let r = Rect::from_min_size(pos2(x0 + i as f32 * (bw + 4.0), y + 5.0 * 28.0), vec2(bw, 22.0));
+        if toggle(app, ui, p, r, &format!("character.lineJoin.{key}"), (label, doc.line_join == join, false)) && enabled {
+            actions.push(json!({"lineJoin": key}));
+        }
+    }
+}
+
 /// The Character panel for the text being edited (or the selected text layer): font family and
 /// style, size, leading, tracking, stroke, scale, baseline shift and other numeric fields, kerning,
 /// fill/stroke colours with eyedroppers, style toggles, OpenType features and variable-font axes.
@@ -224,7 +247,8 @@ pub fn character(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     numeric_fields(app, ui, &p, grid, &doc, &mut actions);
     kerning_field(app, ui, &p, grid, &doc, &mut actions);
     stroke_order_field(app, ui, grid, &doc, &mut actions);
-    y += 5.0 * 28.0 + 8.0;
+    line_join_field(app, ui, &p, grid, &doc, &mut actions);
+    y += 6.0 * 28.0 + 8.0;
     // Fill / stroke swatches with their enable boxes.
     for (i, (key, label, on, c)) in [("fill", "Fill", doc.apply_fill, doc.fill), ("stroke", "Stroke", doc.apply_stroke, doc.stroke)].into_iter().enumerate() {
         let fx = x0 + i as f32 * (w / 2.0);
diff --git a/crates/ui-egui/src/panels/timeline.rs b/crates/ui-egui/src/panels/timeline.rs
index af0cf0e89..98bc4d8d2 100644
--- a/crates/ui-egui/src/panels/timeline.rs
+++ b/crates/ui-egui/src/panels/timeline.rs
@@ -158,11 +158,13 @@ fn with_expr_rows(rows: Vec<Row>, comp: &Comp, tl: &crate::state::TimelineState,
 }
 
 /// A pick-whip drag in progress: (kind, layer, prop uid, start point). The kinds are the
-/// layer's parent pick whip, an expression's and a property's (Parent & Link column).
+/// layer's parent pick whip, an expression's, a property's (Parent & Link column) and the layer's
+/// track matte pick whip.
 type PickWhip = (u8, u64, u64, Pos2);
 const WHIP_PARENT: u8 = 0;
 const WHIP_EXPR: u8 = 1;
 const WHIP_PROP: u8 = 2;
+const WHIP_MATTE: u8 = 3;
 
 /// The `egui::Id` under which a pick-whip drag in progress ([`PickWhip`]) is kept during the
 /// drag.
@@ -170,6 +172,11 @@ fn pick_whip_id() -> egui::Id {
     egui::Id::unique("tl-pickwhip")
 }
 
+/// The layers a layer pick whip (parent, track matte) links, taken as its drag starts.
+fn whip_layers_id() -> egui::Id {
+    egui::Id::unique("tl-pickwhip-layers")
+}
+
 /// The automation id, label and hover hint of a pick whip.
 struct WhipText<'a> {
     auto: &'a str,
@@ -193,7 +200,15 @@ fn pick_whip(
     app.auto.add(auto, rect, label);
     if resp.drag_started() {
         let state: PickWhip = (kind, layer, prop, rect.center());
-        ui.ctx().data_mut(|d| d.insert_temp(pick_whip_id(), state));
+        let selected = &app.session.state.selected_layers;
+        let layers = match (kind, app.session.active_comp()) {
+            (WHIP_MATTE, Some(comp)) => video_targets(comp, LayerId(layer), selected),
+            _ => edited_layers(LayerId(layer), selected),
+        };
+        ui.ctx().data_mut(|d| {
+            d.insert_temp(pick_whip_id(), state);
+            d.insert_temp(whip_layers_id(), layers);
+        });
     }
     resp
 }
@@ -1309,6 +1324,20 @@ fn layer_drag_id() -> egui::Id {
     egui::Id::unique("tl-layer-drag")
 }
 
+/// An effect, mask, shape item or text animator being dragged to a new place among its
+/// siblings (#2210).
+#[derive(Clone)]
+struct GroupDrag {
+    comp: ItemId,
+    owner: egui::Id,
+    layer: LayerId,
+    uid: u64,
+}
+
+fn group_drag_id() -> egui::Id {
+    egui::Id::unique("tl-group-drag")
+}
+
 /// A keyframe drag in progress: where the pointer started, the grabbed key's comp time
 /// (seconds), how many frames the selected keys have moved so far and, for a Quick Offset
 /// (Ctrl/Cmd+Alt), how many layers it staggers.
@@ -1400,8 +1429,9 @@ fn switch_gesture(ui: &egui::Ui, resp: &egui::Response, row: Rect, switch: &'sta
     (a.min(b) < row.max.y && a.max(b) >= row.min.y).then_some((d.value, d.merge))
 }
 
-/// The layers an edit made on `layer`'s row applies to (a switch, its label, its blending mode):
-/// the selection when the row is selected, else that layer alone, as in After Effects.
+/// The layers an edit made on `layer`'s row applies to (a switch, its label, its blending mode,
+/// its parent or track matte, moving its bar): the selection when the row is selected, else that
+/// layer alone, as in After Effects (#1260).
 fn edited_layers(layer: LayerId, selected: &[LayerId]) -> Vec<u64> {
     if selected.contains(&layer) { selected.iter().map(|l| l.0).collect() } else { vec![layer.0] }
 }
@@ -1427,9 +1457,10 @@ fn switch_targets(comp: &Comp, project: &Project, selected: &[LayerId], layer: u
     edited_layers(LayerId(layer), selected).into_iter().filter(|l| comp.layer(LayerId(*l)).is_some_and(|l| switch_applies(l, name, project))).collect()
 }
 
-/// The layers a Modes column edit on `layer`'s row (its blending mode, Preserve Transparency)
-/// acts on: [`edited_layers`] that have video.
-fn mode_targets(comp: &Comp, layer: LayerId, selected: &[LayerId]) -> Vec<u64> {
+/// The layers a Modes column edit (blending mode, Preserve Transparency) or a Track Matte edit
+/// on `layer`'s row acts on: [`edited_layers`] that have video. Selected nulls, cameras and
+/// lights (no Modes or Track Matte on their rows) are left out.
+fn video_targets(comp: &Comp, layer: LayerId, selected: &[LayerId]) -> Vec<u64> {
     edited_layers(layer, selected).into_iter().filter(|l| comp.layer(LayerId(*l)).is_some_and(|l| l.source.is_av())).collect()
 }
 
@@ -1505,7 +1536,7 @@ fn shift_range(ctx: &egui::Context, cid: ItemId, comp: &Comp, rows: &[Row], sele
 /// Where layers dropped at height `py` land among the visible layer rows: above the first row
 /// whose middle is below it (its index in `layer_rows`), else below the last row. Returns that
 /// and the y of the line that shows it (`top` without rows).
-fn insertion(layer_rows: &[(Rect, LayerId)], py: f32, top: f32) -> (Option<usize>, f32) {
+fn insertion<T>(layer_rows: &[(Rect, T)], py: f32, top: f32) -> (Option<usize>, f32) {
     let at = layer_rows.iter().position(|(r, _)| py < r.center().y);
     let y = match at {
         Some(i) => layer_rows.get(i).map_or(top, |(r, _)| r.min.y),
@@ -1540,7 +1571,7 @@ fn replaceable_item(it: &effectcraft_engine::project::Item) -> bool {
 
 /// The Alt/Option-drag target: the layer under the pointer can take this item as its source, and
 /// the item wouldn't put the composition inside itself.
-fn replace_source_target(app: &EffectcraftApp, cid: ItemId, item: ItemId, lid: LayerId, comp: &Comp) -> bool {
+pub(crate) fn replace_source_target(app: &EffectcraftApp, cid: ItemId, item: ItemId, lid: LayerId, comp: &Comp) -> bool {
     app.session.project.item(item).is_some_and(replaceable_item)
         && !app.session.project.comp_contains(item, cid)
         && comp
@@ -1848,7 +1879,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     pick_whip_edge_scroll(app, g);
     let snap_project = app.session.project.clone();
     let snap_expr = app.session.expr.clone();
-    let ectx = EvalCtx { project: &snap_project, comp_id: cid, comp: &comp, time: g.time, expr: snap_expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &snap_project,
+        comp_id: cid,
+        comp: &comp,
+        time: g.time,
+        expr: snap_expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let mut rw = begin_rows(app, ui, tl);
     let g = &mut rw;
     draw_rows(app, ui, g, &ectx);
@@ -1859,6 +1899,7 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     alt_scale_and_graph(app, ui, g, &ectx);
     graph_empty_area(ui, g);
     layer_reorder_drag(ui, g);
+    group_reorder_drag(ui, g);
     quick_offset_follow(g);
     key_drag_follow(app, g);
     key_box_select(app, ui, g);
@@ -3013,7 +3054,7 @@ fn layer_mode_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
     let opts: Vec<String> =
         BlendMode::ALL.iter().flat_map(|m| if m.ends_group() { vec![m.label().to_string(), "-".to_string()] } else { vec![m.label().to_string()] }).collect();
     if let Some(i) = widgets::popup_menu(ui, pop, mr.left_bottom(), &opts, opts.iter().position(|o| o == layer.blend_mode.label())) {
-        actions.push(("layer.setBlendMode".into(), json!({"layers": mode_targets(&comp, layer.id, selected), "mode": opts[i]})));
+        actions.push(("layer.setBlendMode".into(), json!({"layers": video_targets(&comp, layer.id, selected), "mode": opts[i]})));
     }
     let tr = Rect::from_center_size(pos2(cw.mode + 76.0 + 6.0, cy), vec2(14.0, 14.0));
     app.auto.add(&format!("timeline.layer.{}.preserveTransparency", layer.id.0), tr, "Preserve Transparency");
@@ -3023,7 +3064,7 @@ fn layer_mode_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
         actions.push((
             "layer.setSwitch".into(),
             json!({
-                "layers": mode_targets(&comp, layer.id, selected),
+                "layers": video_targets(&comp, layer.id, selected),
                 "switch": "preserveTransparency",
                 "value": !layer.preserve_transparency
             }),
@@ -3037,10 +3078,25 @@ fn layer_matte_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
     let comp = g.tl.comp.clone();
     let cw = &g.tl.cw;
     let actions = &mut g.tl.actions;
+    let lp = g.lp.clone();
+    let selected = &g.selected;
     let layer = rc.layer;
     let cy = rc.cy;
-    // Track matte: layer picker + kind.
-    let mr = Rect::from_min_size(pos2(cw.trkmat + 2.0, cy - 9.0), vec2(104.0, 18.0));
+    // Track matte: a pick whip, then the layer picker with the mode. Like the parent, they set
+    // the matte of every selected layer when the row is selected (#1260).
+    pick_whip(
+        app,
+        ui,
+        &lp,
+        Rect::from_center_size(pos2(cw.trkmat + 9.0, cy), vec2(15.0, 15.0)),
+        (WHIP_MATTE, layer.id.0, 0),
+        WhipText {
+            auto: &format!("timeline.layer.{}.trackMattePickWhip", layer.id.0),
+            label: "Track Matte pick whip",
+            hint: crate::i18n::tr("Track Matte pick whip: drag onto a layer"),
+        },
+    );
+    let mr = Rect::from_min_size(pos2(cw.trkmat + 20.0, cy - 9.0), vec2(88.0, 18.0));
     let label = match layer.track_matte {
         Some(m) => comp.layer(m.layer).map(|l| format!("{} {}", comp.index_of(l.id).unwrap_or(0), l.name)).unwrap_or("None".into()),
         None => "No Track Matte".into(),
@@ -3070,7 +3126,7 @@ fn layer_matte_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
     let current = layer.track_matte.and_then(|m| opts.iter().position(|o| o == m.kind.label()));
     if let Some(i) = widgets::popup_menu(ui, pop, mr.left_bottom(), &opts, current) {
         let ids: Vec<LayerId> = candidates.iter().map(|l| l.id).collect();
-        if let Some(a) = opts.get(i).and_then(|o| track_matte_pick(layer, &ids, i, o)) {
+        if let Some(a) = opts.get(i).and_then(|o| track_matte_pick(&video_targets(&comp, layer.id, selected), &ids, i, o)) {
             actions.push(a);
         }
     }
@@ -3087,6 +3143,7 @@ fn layer_parent_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc
     let cw = &g.tl.cw;
     let actions = &mut g.tl.actions;
     let lp = g.lp.clone();
+    let selected = &g.selected;
     let layer = rc.layer;
     let cy = rc.cy;
     pick_whip(
@@ -3118,8 +3175,10 @@ fn layer_parent_cell(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc
         }
     }
     if let Some(i) = widgets::popup_menu(ui, pop, pr_rect.left_bottom(), &popts, None) {
-        let par = if i == 0 { serde_json::Value::Null } else { json!(cands[i - 2].id.0) };
-        actions.push(("layer.setParent".into(), json!({"layers": [layer.id.0], "parent": par})));
+        let par = cands.get(i.wrapping_sub(2)).map(|l| l.id.0);
+        // (The new parent itself, if selected, stays as it is.)
+        let layers: Vec<u64> = edited_layers(layer.id, selected).into_iter().filter(|l| Some(*l) != par).collect();
+        actions.push(("layer.setParent".into(), json!({"layers": layers, "parent": par})));
     }
 }
 
@@ -3287,7 +3346,6 @@ fn layer_bar_drag(g: &mut Rw, rc: &RowCtx<'_>, bars: &BarResps, quick: bool) {
     let selected = &g.selected;
     let ui_actions = &mut g.ui_actions;
     let layer = rc.layer;
-    let is_sel = rc.is_sel;
     let drag_key = format!("bar-{}", layer.id.0);
     for (resp, kind) in [(&body, "move"), (&lin, "in"), (&lout, "out")] {
         if kind == "move" && quick {
@@ -3303,7 +3361,7 @@ fn layer_bar_drag(g: &mut Rw, rc: &RowCtx<'_>, bars: &BarResps, quick: bool) {
                 let d = frames as f64 * fd;
                 // Moving or trimming a selected layer acts on the whole
                 // selection; each layer trims from its own in/out point.
-                let targets = if is_sel { json!(selected.iter().map(|l| l.0).collect::<Vec<_>>()) } else { json!([layer.id.0]) };
+                let targets = json!(edited_layers(layer.id, selected));
                 let params = match kind {
                     "move" => json!({"layers": targets, "delta": d, "merge": drag_key}),
                     "in" => json!({"layers": targets, "inDelta": d, "merge": drag_key}),
@@ -3516,6 +3574,7 @@ fn group_mask_mode(ui: &mut egui::Ui, g: &mut Rw, rc: &RowCtx<'_>) {
 
 /// Group row click and double-click.
 fn group_row_click(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc: &RowCtx<'_>) {
+    let cid = g.tl.cid;
     let cw = &g.tl.cw;
     let actions = &mut g.tl.actions;
     let ui_actions = &mut g.ui_actions;
@@ -3524,7 +3583,12 @@ fn group_row_click(app: &mut EffectcraftApp, ui: &mut egui::Ui, g: &mut Rw, rc:
     let indent = rc.indent;
     let RowKind::Group { uid, name, fx, .. } = &rc.row.kind else { return };
     let gr_rect = Rect::from_min_max(pos2(indent + 8.0, r.min.y), pos2(cw.switches, r.max.y));
-    let gr = ui.interact(gr_rect, egui::Id::unique(("grow", uid)), Sense::click());
+    // Effects, masks, shape items and animators drag to a new place among their siblings.
+    let movable = !layer.switches.locked && layer.props.find_group(*uid).is_some_and(PropGroup::is_instance);
+    let gr = ui.interact(gr_rect, egui::Id::unique(("grow", uid)), if movable { Sense::click_and_drag() } else { Sense::click() });
+    if movable && gr.drag_started_by(egui::PointerButton::Primary) {
+        ui.ctx().data_mut(|d| d.insert_temp(group_drag_id(), GroupDrag { comp: cid, owner: gr.id, layer: layer.id, uid: *uid }));
+    }
     app.auto.add(&format!("timeline.group.{uid}.name"), gr_rect, name);
     if gr.clicked() && uid & (WAVE_BIT | GEOM_BIT) == 0 {
         actions.push(("prop.select".into(), json!({"layer": layer.id.0, "prop": uid, "selectKeys": false})));
@@ -4260,6 +4324,7 @@ fn pick_whip_drag(g: &mut Rw) {
     let t = g.tl.t;
     let graph_x0 = g.tl.graph_x0;
     let ctx = g.tl.ctx.clone();
+    let comp = g.tl.comp.clone();
     let actions = &mut g.tl.actions;
     let hit_rows = &mut g.hit_rows;
     let dim_hits = &mut g.dim_hits;
@@ -4272,7 +4337,7 @@ fn pick_whip_drag(g: &mut Rw) {
         let target = hit_rows.iter().find(|(r, _)| r.contains(ptr)).map(|(r, row)| (*r, row.clone()));
         // Shown this pass or the last one (Effect Controls may draw after the Timeline).
         let pass = ctx.cumulative_pass_nr();
-        let elsewhere = (target.is_none() && kind != WHIP_PARENT)
+        let elsewhere = (target.is_none() && !matches!(kind, WHIP_PARENT | WHIP_MATTE))
             .then(|| ctx.data(|d| d.get_temp::<WhipTargets>(whip_targets_id())))
             .flatten()
             .filter(|(p, _)| p.saturating_add(1) >= pass)
@@ -4283,10 +4348,13 @@ fn pick_whip_drag(g: &mut Rw) {
             fg.rect_stroke(*tr, 0.0, Stroke::new(1.0, t.accent), StrokeKind::Inside);
         }
         if ctx.input(|i| !i.pointer.any_down()) {
-            ctx.data_mut(|d| {
+            let whip_layers = ctx.data_mut(|d| {
                 d.remove::<PickWhip>(pick_whip_id());
                 d.remove::<WhipTargets>(whip_targets_id());
+                d.remove_temp::<Vec<u64>>(whip_layers_id())
             });
+            // The layers a layer pick whip links, less the one it was dropped on.
+            let linked = |onto: u64| -> Vec<u64> { whip_layers.clone().unwrap_or_else(|| vec![src_layer]).into_iter().filter(|l| *l != onto).collect() };
             let into = (kind == WHIP_EXPR).then(|| ctx.data_mut(|d| d.remove_temp::<WhipInto>(whip_into_id(src_prop)))).flatten();
             // The property dropped on, and the value (dimension) if on one of them: `position[0]`.
             let dim = |fields: &[Rect]| fields.iter().position(|r| r.contains(ptr));
@@ -4299,7 +4367,11 @@ fn pick_whip_drag(g: &mut Rw) {
             };
             match (kind, target, prop_target) {
                 (WHIP_PARENT, Some((_, row)), _) if row.layer.0 != src_layer => {
-                    actions.push(("layer.setParent".into(), json!({"layers": [src_layer], "parent": row.layer.0})));
+                    actions.push(("layer.setParent".into(), json!({"layers": linked(row.layer.0), "parent": row.layer.0})));
+                }
+                // Each layer keeps its own matte mode.
+                (WHIP_MATTE, Some((_, row)), _) if row.layer.0 != src_layer && comp.layer(row.layer).is_some_and(|l| l.source.is_av()) => {
+                    actions.push(("layer.setTrackMatte".into(), json!({"layers": linked(row.layer.0), "matte": row.layer.0, "kind": "preserve"})));
                 }
                 // The property pick whip replaces the expression with the reference (or adds one),
                 // as the expression pick whip does when its expression isn't being edited.
@@ -4430,6 +4502,50 @@ fn layer_reorder_drag(ui: &mut egui::Ui, g: &mut Rw) {
     // Quick Offset of layer bars: the last selected layer moves by whole frames with the pointer
 }
 
+/// Group reorder drag (#2210): a line where the dragged effect, mask or shape item lands among
+/// its siblings; the drop moves it there (`prop.moveGroup`). Escape cancels.
+fn group_reorder_drag(ui: &mut egui::Ui, g: &mut Rw) {
+    let ctx = g.tl.ctx.clone();
+    let comp = g.tl.comp.clone();
+    let Some(drag) = ctx.data(|d| d.get_temp::<GroupDrag>(group_drag_id())) else { return };
+    let (down, released, escape) =
+        ctx.input(|i| (i.pointer.primary_down(), i.pointer.button_released(egui::PointerButton::Primary), i.key_pressed(egui::Key::Escape)));
+    let dropped = ctx.drag_stopped_id() == Some(drag.owner) && released;
+    let parent = comp.layer(drag.layer).and_then(|l| l.props.parent_of(drag.uid));
+    let valid = ui.is_enabled() && drag.comp == g.tl.cid && parent.is_some() && !escape && (dropped || (down && ctx.dragged_id() == Some(drag.owner)));
+    if dropped || !valid {
+        ctx.data_mut(|d| d.remove::<GroupDrag>(group_drag_id()));
+    }
+    let Some(parent) = parent.filter(|_| valid) else { return };
+    let siblings: Vec<u64> = parent.children.iter().map(Node::uid).collect();
+    let rows: Vec<(Rect, u64)> = g
+        .hit_rows
+        .iter()
+        .filter_map(|(r, row)| match &row.kind {
+            RowKind::Group { uid, .. } if row.layer == drag.layer && siblings.contains(uid) => Some((*r, *uid)),
+            _ => None,
+        })
+        .collect();
+    let Some(py) = ui.input(|i| i.pointer.interact_pos().or(i.pointer.latest_pos())).map(|p| p.y) else { return };
+    if rows.is_empty() {
+        return;
+    }
+    let (at, line_y) = insertion(&rows, py, g.tl.rows_rect.min.y);
+    if !dropped {
+        ctx.set_cursor_icon(egui::CursorIcon::Grabbing);
+        g.tl.p.with_clip_rect(g.tl.rows_rect).line_segment([pos2(g.tl.rect.min.x, line_y), pos2(g.tl.graph_x0, line_y)], Stroke::new(2.0, g.tl.t.accent));
+        return;
+    }
+    // The sibling the drop lands before (or after, below the last visible one).
+    let Some(&(_, anchor)) = at.map_or(rows.last(), |i| rows.get(i)) else { return };
+    let from = siblings.iter().position(|u| *u == drag.uid);
+    let rest: Vec<u64> = siblings.iter().copied().filter(|u| *u != drag.uid).collect();
+    let to = if anchor == drag.uid { from } else { rest.iter().position(|u| *u == anchor).map(|i| i + usize::from(at.is_none())) };
+    if let Some(to) = to.filter(|to| Some(*to) != from) {
+        g.tl.actions.push(("prop.moveGroup".into(), json!({"layer": drag.layer.0, "prop": drag.uid, "index": to + 1})));
+    }
+}
+
 /// Quick Offset of layer bars follows the pointer.
 fn quick_offset_follow(g: &mut Rw) {
     let t = g.tl.t;
@@ -5141,19 +5257,21 @@ fn text_anim_popups(
     }
 }
 
-/// The command for the Track Matte menu item `i` (`choice`) of `layer`, whose menu lists "No Track
-/// Matte", a separator, the matte `candidates`, a separator and the modes. A mode without a matte
-/// layer takes the layer above, like Layer ▸ Track Matte (#864: it used to do nothing).
-fn track_matte_pick(layer: &Layer, candidates: &[LayerId], i: usize, choice: &str) -> Option<(String, serde_json::Value)> {
+/// The command for the Track Matte menu item `i` (`choice`) of a row, setting `layers`' mattes,
+/// whose menu lists "No Track Matte", a separator, the matte `candidates`, a separator and the
+/// modes. A new matte layer keeps each layer's mode (the matte itself, if among them, is left
+/// out); a mode without a matte layer takes the layer above, like Layer ▸ Track Matte (#864: it
+/// used to do nothing).
+fn track_matte_pick(layers: &[u64], candidates: &[LayerId], i: usize, choice: &str) -> Option<(String, serde_json::Value)> {
     if i == 0 {
-        return Some(("layer.setTrackMatte".into(), json!({"layer": layer.id.0, "matte": null})));
+        return Some(("layer.setTrackMatte".into(), json!({"layers": layers, "matte": null})));
     }
     if let Some(m) = i.checked_sub(2).and_then(|j| candidates.get(j)) {
-        let kind = layer.track_matte.map(|m| m.kind).unwrap_or_default();
-        return Some(("layer.setTrackMatte".into(), json!({"layer": layer.id.0, "matte": m.0, "kind": kind_name(kind)})));
+        let layers: Vec<u64> = layers.iter().copied().filter(|l| *l != m.0).collect();
+        return (!layers.is_empty()).then(|| ("layer.setTrackMatte".into(), json!({"layers": layers, "matte": m.0, "kind": "preserve"})));
     }
     let k = MatteKind::ALL.into_iter().find(|k| k.label() == choice)?;
-    Some(("layer.trackMatte".into(), json!({"layers": [layer.id.0], "op": kind_name(k)})))
+    Some(("layer.trackMatte".into(), json!({"layers": layers, "op": kind_name(k)})))
 }
 
 fn kind_name(k: MatteKind) -> &'static str {
@@ -5486,7 +5604,8 @@ fn value_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>,
 fn scalar_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>, actions: &mut Vec<(String, serde_json::Value)>, value: &Value) {
     let Value::Scalar(v) = value else { return };
     let (layer, prop, at, uid) = (ve.layer, ve.prop, ve.at, ve.uid);
-    let t = app.tokens;
+    // The values themselves: red while an expression drives the property (#1306).
+    let vt = app.tokens.for_value(prop.has_expression());
     let (x, y) = (at.x, at.y - 9.0);
     let (min, max, dec, speed) = match &prop.ui {
         ParamUi::Slider { min, max, decimals, .. } => (*min, *max, *decimals as usize, widgets::slider_scrub_speed(&prop.ui)),
@@ -5494,7 +5613,7 @@ fn scalar_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>
         _ => (-1e9, 1e9, 1, 1.0),
     };
     if matches!(prop.ui, ParamUi::Angle) {
-        let (rr, dr, nv) = super::fx_widgets::angle_field(ui, pos2(x, y), egui::Id::unique(("v", uid, 0)), *v, 1, &t);
+        let (rr, dr, nv) = super::fx_widgets::angle_field(ui, pos2(x, y), egui::Id::unique(("v", uid, 0)), *v, 1, &vt);
         app.auto.add(&format!("timeline.prop.{uid}.value"), dr, &prop.name);
         app.auto.add(&format!("timeline.prop.{uid}.revolutions"), rr, &prop.name);
         if let Some(nv) = nv {
@@ -5510,7 +5629,7 @@ fn scalar_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>
             egui::Id::unique(("v", uid, 0)),
             *v,
             &widgets::HotSpec { speed, range: (min, max), decimals: dec.max(1), suffix },
-            &t,
+            &vt,
         );
         app.auto.add(&format!("timeline.prop.{uid}.value"), r, &prop.name);
         if let Some(nv) = nv {
@@ -5523,6 +5642,7 @@ fn scalar_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>
 fn vector_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>, actions: &mut Vec<(String, serde_json::Value)>, value: &Value) -> Vec<Rect> {
     let (p, layer, prop, at, uid) = (ve.p, ve.layer, ve.prop, ve.at, ve.uid);
     let t = app.tokens;
+    let vt = t.for_value(prop.has_expression());
     let (mut x, y) = (at.x, at.y - 9.0);
     let is_3d = layer.is_3d();
     let mut dims = vec![];
@@ -5555,7 +5675,7 @@ fn vector_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>
             egui::Id::unique(("v", uid, d)),
             c[d],
             &widgets::HotSpec { speed: if pct { 0.5 } else { 1.0 }, range, decimals: 1, suffix },
-            &t,
+            &vt,
         );
         app.auto.add(&format!("timeline.prop.{uid}.value.{d}"), r, &prop.name);
         dims.push(r);
@@ -5578,7 +5698,7 @@ fn vector_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>
         }
         x = r.max.x + if d + 1 < n { 2.0 } else { 0.0 };
         if d + 1 < n {
-            p.text(pos2(x, at.y), Align2::LEFT_CENTER, ",", Tokens::ui(12.0), t.hot_text);
+            p.text(pos2(x, at.y), Align2::LEFT_CENTER, ",", Tokens::ui(12.0), vt.hot_text);
             x += 6.0;
         }
     }
@@ -5653,7 +5773,7 @@ fn enum_editor(app: &mut EffectcraftApp, ui: &mut egui::Ui, ve: &ValueEdit<'_>,
             ve.set(actions, json!(ni));
         }
     } else {
-        p.text(pos2(x, at.y), Align2::LEFT_CENTER, fmt_num(*i as f64, 0), Tokens::ui(12.0), t.hot_text);
+        p.text(pos2(x, at.y), Align2::LEFT_CENTER, fmt_num(*i as f64, 0), Tokens::ui(12.0), t.for_value(prop.has_expression()).hot_text);
     }
 }
 
diff --git a/crates/ui-egui/src/panels/timeline/tests.rs b/crates/ui-egui/src/panels/timeline/tests.rs
index d05787a18..12259abf7 100644
--- a/crates/ui-egui/src/panels/timeline/tests.rs
+++ b/crates/ui-egui/src/panels/timeline/tests.rs
@@ -79,7 +79,7 @@ fn a_track_matte_mode_without_a_matte_takes_the_layer_above() {
     let (bottom, matte, top) = (find(&s, "Chain Bottom"), find(&s, "Matte"), find(&s, "Chain Top"));
     let candidates = [top.id, matte.id];
     let pick = |s: &mut effectcraft_engine::Session, name: &str, i: usize, choice: &str| {
-        let (id, params) = track_matte_pick(&find(s, name), &candidates, i, choice).expect("a menu item is an action");
+        let (id, params) = track_matte_pick(&[find(s, name).id.0], &candidates, i, choice).expect("a menu item is an action");
         s.execute(&id, params)
     };
     pick(&mut s, "Chain Bottom", 5, "Alpha Inverted Matte").unwrap();
@@ -97,7 +97,7 @@ fn a_track_matte_mode_without_a_matte_takes_the_layer_above() {
     assert!(pick(&mut s, "Chain Top", 5, "Alpha Matte").is_err());
     pick(&mut s, "Chain Bottom", 0, "No Track Matte").unwrap();
     assert!(find(&s, "Chain Bottom").track_matte.is_none());
-    assert!(track_matte_pick(&bottom, &candidates, 1, "-").is_none(), "a separator does nothing");
+    assert!(track_matte_pick(&[bottom.id.0], &candidates, 1, "-").is_none(), "a separator does nothing");
 }
 
 /// #957: vector footage gets the Continuously Rasterize switch; raster footage does not.
diff --git a/crates/ui-egui/src/panels/viewer.rs b/crates/ui-egui/src/panels/viewer.rs
index cfada4728..8c619c9c1 100644
--- a/crates/ui-egui/src/panels/viewer.rs
+++ b/crates/ui-egui/src/panels/viewer.rs
@@ -178,7 +178,16 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
     phase_frame(app, &mut v);
     let snap_project = app.session.project.clone();
     let snap_expr = app.session.expr.clone();
-    let ectx = EvalCtx { project: &snap_project, comp_id: cid, comp: &comp, time: v.time, expr: snap_expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &snap_project,
+        comp_id: cid,
+        comp: &comp,
+        time: v.time,
+        expr: snap_expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     phase_guides(app, &ectx, &mut v);
     phase_layers(app, ui, &ectx, &mut v);
     phase_scene(app, &ectx, &mut v);
@@ -935,11 +944,14 @@ fn phase_hover(app: &mut EffectcraftApp, ui: &mut egui::Ui, ectx: &EvalCtx, resp
             }
         };
         ctx.set_cursor_icon(cursor);
-        // Scroll wheel zooms around the pointer.
-        let scroll = ui.input(|i| i.smooth_scroll_delta.y + i.zoom_delta().ln() * 300.0);
-        if scroll.abs() > 0.1 && area.contains(hp) {
-            let k = (scroll / 300.0).exp();
-            let nz = (zoom * k).clamp(0.01, 32.0);
+        // The mouse wheel and a trackpad pinch zoom around the pointer; a two-finger trackpad
+        // scroll pans.
+        let scroll = super::viewer_scroll(&ctx);
+        if scroll.pan != egui::Vec2::ZERO && area.contains(hp) {
+            app.ui.viewer.pan = [app.ui.viewer.pan[0] + scroll.pan.x, app.ui.viewer.pan[1] + scroll.pan.y];
+        }
+        if (scroll.zoom - 1.0).abs() > 3e-4 && area.contains(hp) {
+            let nz = (zoom * scroll.zoom).clamp(0.01, 32.0);
             let before = map.to_comp(hp);
             let new_origin = hp - vec2(before[0] as f32 * nz, before[1] as f32 * nz);
             let new_center = new_origin + vec2(cw * nz / 2.0, ch * nz / 2.0);
@@ -1252,6 +1264,39 @@ fn phase_dragstart(app: &mut EffectcraftApp, ui: &mut egui::Ui, ectx: &EvalCtx,
     v.puppet_layers = puppet_layers;
 }
 
+/// Auto-pan (#999): a mask vertex, tangent or Pen drag held at (or past) the edge of the view
+/// pans it, as in After Effects, so the point moves on past what was visible. Returns the map
+/// of the panned view.
+fn edge_pan(app: &mut EffectcraftApp, ctx: &egui::Context, g: &Gesture, map: ViewerMap, pos: Pos2) -> ViewerMap {
+    if !matches!(g, Gesture::Vertices { .. } | Gesture::Tangent { .. } | Gesture::Pen { .. }) {
+        return map;
+    }
+    let d = edge_pan_speed(map.area, pos) * ctx.input(|i| i.stable_dt).min(0.1);
+    if d == egui::Vec2::ZERO {
+        return map;
+    }
+    app.ui.viewer.pan = [app.ui.viewer.pan[0] + d.x, app.ui.viewer.pan[1] + d.y];
+    ctx.request_repaint();
+    ViewerMap { origin: map.origin + d, ..map }
+}
+
+/// How fast (points per second, per axis) the view pans under a drag at `pos`: within 24 points
+/// of an edge of `area`, or past it, toward that edge and faster the further out.
+fn edge_pan_speed(area: Rect, pos: Pos2) -> egui::Vec2 {
+    const ZONE: f32 = 24.0;
+    let axis = |p: f32, lo: f32, hi: f32| {
+        let depth = if p < lo + ZONE {
+            lo + ZONE - p
+        } else if p > hi - ZONE {
+            hi - ZONE - p
+        } else {
+            0.0
+        };
+        (depth / ZONE).clamp(-3.0, 3.0) * 400.0
+    };
+    vec2(axis(pos.x, area.min.x, area.max.x), axis(pos.y, area.min.y, area.max.y))
+}
+
 fn phase_drag(app: &mut EffectcraftApp, ui: &mut egui::Ui, ectx: &EvalCtx, resp: &egui::Response, v: &mut Vw<'_>) {
     let t = v.t;
     let zoom = v.zoom;
@@ -1262,6 +1307,7 @@ fn phase_drag(app: &mut EffectcraftApp, ui: &mut egui::Ui, ectx: &EvalCtx, resp:
     let painter = v.painter.clone();
     let gesture: Option<Gesture> = ui.data(|d| d.get_temp(gid));
     if let (Some(g), Some(pos)) = (gesture.clone(), resp.interact_pointer_pos()) {
+        let map = edge_pan(app, &ctx, &g, map, pos);
         let cpt = map.to_comp(pos);
         let merge = format!("viewer-drag-{}", ui.data(|d| d.get_temp::<u64>(egui::Id::unique("viewer-drag-n")).unwrap_or(0)));
         match g {
@@ -1809,7 +1855,7 @@ use geometry::{
 pub(crate) use geometry::{from_effect_space, fx2c, l2c, layer_outline, layer_quad};
 use gesture::{Gesture, HANDLE, ROTO_HINT, pen_id, roi_drag, roi_handles, vertex_grab_radius};
 use shapes::{create_shape, draw_shape_ghost, shape_drag};
-pub(crate) use shapes::{layer_at, layers_at, pick, selectable_layers};
+pub(crate) use shapes::{layer_at, layer_at_including_locked, layers_at, pick, selectable_layers};
 #[cfg(test)]
 use tools::constrain_45;
 use tools::{add_motion_key, axis_at, axis_drag, drag_axes, draw_rigs, parent_world_inverse, pen_cursor, pen_cursor_icon, pen_press, select_motion_key};
diff --git a/crates/ui-egui/src/panels/viewer/shapes.rs b/crates/ui-egui/src/panels/viewer/shapes.rs
index 395219a05..0cd579883 100644
--- a/crates/ui-egui/src/panels/viewer/shapes.rs
+++ b/crates/ui-egui/src/panels/viewer/shapes.rs
@@ -4,14 +4,17 @@ use super::{
     pos2,
 };
 
-/// Visible, unlocked layers eligible for viewer hit tests, in front-to-back order.
+/// Visible layers eligible for viewer hit tests, locked or not, in front-to-back order.
 /// Solo scope matches the renderer: any soloed AV layer activates it at every time (as in After
 /// Effects), even when hidden, locked or outside its in-out range.
-pub(crate) fn selectable_layers(comp: &Comp, time: Tick) -> impl Iterator<Item = &Layer> {
+fn hit_testable_layers(comp: &Comp, time: Tick) -> impl Iterator<Item = &Layer> {
     let any_solo = comp.layers.iter().any(|l| l.switches.solo && l.source.is_av());
-    comp.layers
-        .iter()
-        .filter(move |l| l.is_active_at(time) && l.switches.video && !l.switches.locked && !l.is_camera() && !l.is_light() && (!any_solo || l.switches.solo))
+    comp.layers.iter().filter(move |l| l.is_active_at(time) && l.switches.video && !l.is_camera() && !l.is_light() && (!any_solo || l.switches.solo))
+}
+
+/// Visible, unlocked layers eligible for viewer hit tests, in front-to-back order.
+pub(crate) fn selectable_layers(comp: &Comp, time: Tick) -> impl Iterator<Item = &Layer> {
+    hit_testable_layers(comp, time).filter(|l| !l.switches.locked)
 }
 
 /// Selectable layers under a comp point, front to back.
@@ -24,6 +27,18 @@ pub(crate) fn layer_at<'a>(ectx: &EvalCtx<'a>, cpt: [f64; 2]) -> Option<&'a Laye
     layers_at(ectx, cpt).next()
 }
 
+/// Topmost visible layer under a comp point, locked or not. An Alt-drop uses it so a locked layer in
+/// front is refused rather than skipped, which would replace the layer behind it.
+pub(crate) fn layer_at_including_locked<'a>(ectx: &EvalCtx<'a>, cpt: [f64; 2]) -> Option<&'a Layer> {
+    // A layer scaled to nothing has a degenerate quad that `point_in_quad` accepts everywhere.
+    hit_testable_layers(ectx.comp, ectx.time).find(|l| layer_quad(ectx, l).is_some_and(|(_, q, _)| quad_area(&q) > 1e-9 && point_in_quad(cpt, &q)))
+}
+
+/// Area of a quad (shoelace formula); zero when its corners coincide or are collinear.
+fn quad_area(q: &[[f64; 2]; 4]) -> f64 {
+    (0..4).map(|i| q[i][0] * q[(i + 1) % 4][1] - q[(i + 1) % 4][0] * q[i][1]).sum::<f64>().abs() / 2.0
+}
+
 /// The layer a press at a comp point acts on, selected (Shift toggles the topmost layer). As in
 /// After Effects, a selected layer under the point comes before the layers in front of it, so it
 /// can be dragged where they cover it; otherwise the topmost layer (#230).
@@ -202,6 +217,8 @@ pub(super) fn create_shape(app: &mut EffectcraftApp, tool: Tool, a: [f64; 2], b:
                 time: app.session.time(),
                 expr: None,
                 footage: None,
+                property_overrides: &[],
+                media_overrides: &[],
             };
             let inv = l2c(&ectx, &l).0.inverse().unwrap_or(Mat3::IDENTITY);
             let p0 = inv.apply(gv2(cx - w / 2.0, cy - h / 2.0));
diff --git a/crates/ui-egui/src/panels/viewer/tests.rs b/crates/ui-egui/src/panels/viewer/tests.rs
index cb5bffe65..f9d3ef2f4 100644
--- a/crates/ui-egui/src/panels/viewer/tests.rs
+++ b/crates/ui-egui/src/panels/viewer/tests.rs
@@ -139,3 +139,15 @@ fn gizmo_segments_clip_at_the_near_plane() {
     assert!(s[1][0] > 10.0 && s[1][0].is_finite(), "toward the camera it grows, never flips: {s:?}");
     assert!(project_segment(&pc, vec3(0.0, 0.0, -200.0), vec3(0.0, 0.0, -300.0)).is_none());
 }
+
+/// #999: a vertex drag pans the view only near or past the edge, toward it, faster further out.
+#[test]
+fn edge_pan_speed_moves_toward_the_edge() {
+    let area = Rect::from_min_max(pos2(100.0, 50.0), pos2(900.0, 650.0));
+    assert_eq!(edge_pan_speed(area, pos2(500.0, 350.0)), egui::Vec2::ZERO);
+    let left = edge_pan_speed(area, pos2(105.0, 350.0));
+    assert!(left.x > 0.0 && left.y == 0.0, "near the left edge the view moves right to show more: {left:?}");
+    assert!(edge_pan_speed(area, pos2(20.0, 350.0)).x > left.x, "faster past the edge");
+    let corner = edge_pan_speed(area, pos2(950.0, 700.0));
+    assert!(corner.x < 0.0 && corner.y < 0.0, "{corner:?}");
+}
diff --git a/crates/ui-egui/src/panels/viewer/view.rs b/crates/ui-egui/src/panels/viewer/view.rs
index 30b3f4d00..59e3e513d 100644
--- a/crates/ui-egui/src/panels/viewer/view.rs
+++ b/crates/ui-egui/src/panels/viewer/view.rs
@@ -44,7 +44,16 @@ pub(super) fn aux_views(
     // layout shows them), evaluated on a snapshot of the project.
     let snap_project = app.session.project.clone();
     let snap_expr = app.session.expr.clone();
-    let ectx = EvalCtx { project: &snap_project, comp_id: cid, comp, time: t, expr: snap_expr.as_deref(), footage: None };
+    let ectx = EvalCtx {
+        project: &snap_project,
+        comp_id: cid,
+        comp,
+        time: t,
+        expr: snap_expr.as_deref(),
+        footage: None,
+        property_overrides: &[],
+        media_overrides: &[],
+    };
     let selected = app.session.state.selected_layers.clone();
     let mut picked: Option<(usize, View3D)> = None;
     for (i, (r, v)) in aux.into_iter().enumerate() {
diff --git a/crates/ui-egui/src/panels/viewer_drop.rs b/crates/ui-egui/src/panels/viewer_drop.rs
index 44364a49d..ac56d9acb 100644
--- a/crates/ui-egui/src/panels/viewer_drop.rs
+++ b/crates/ui-egui/src/panels/viewer_drop.rs
@@ -1,7 +1,8 @@
 //! Dropping onto the Composition viewer: footage, comps and solids from the
 //! Project panel and files from the Media Browser become layers centred where they are dropped
 //! (#85), and an effect or animation preset from Effects & Presets goes on the layer under the
-//! pointer, outlined while it is dragged (#88). Agents do the same with `layer.addItem {position}`,
+//! pointer, outlined while it is dragged (#88). Alt/Option-dropping a Project item replaces the source of
+//! the layer under the pointer instead, as in the Timeline (#2173). Agents do the same with `layer.addItem {position}`,
 //! `mediaBrowser.import {position}`, `effect.apply {layers}` and the preset commands.
 
 use effectcraft_engine::project::{ItemId, ItemKind};
@@ -10,7 +11,7 @@ use egui::{Rect, Stroke, StrokeKind, vec2};
 use serde_json::{Value, json};
 
 use super::DragPayload;
-use super::viewer::{ViewerMap, layer_at, layer_quad};
+use super::viewer::{ViewerMap, layer_at, layer_at_including_locked, layer_quad};
 use crate::EffectcraftApp;
 
 /// While something is dragged over the viewer, show where it goes; drop it on release.
@@ -23,6 +24,9 @@ pub(crate) fn show(app: &mut EffectcraftApp, ui: &egui::Ui, painter: &egui::Pain
     let Some(ptr) = ctx.input(|i| i.pointer.hover_pos()).filter(|_| ui.rect_contains_pointer(map.area)) else { return };
     let stroke = Stroke::new(2.0, app.tokens.accent);
     let at = map.to_comp(ptr);
+    // Alt/Option-drop of a Project item replaces the source of the layer under the pointer (After
+    // Effects), as in the Timeline; it never adds a layer.
+    let alt_item = ctx.input(|i| i.modifiers.alt) && matches!(payload.as_ref(), DragPayload::Item(_));
     let actions: Vec<(&str, Value)> = match payload.as_ref() {
         DragPayload::Effect(effect) => layer_at(ectx, at)
             .map(|l| {
@@ -42,6 +46,7 @@ pub(crate) fn show(app: &mut EffectcraftApp, ui: &egui::Ui, painter: &egui::Pain
             })
             .into_iter()
             .collect(),
+        DragPayload::Item(item) if alt_item => alt_replace(app, ectx, painter, map, stroke, at, *item).into_iter().collect(),
         DragPayload::Item(item) => {
             // The layer's frame, centred on the pointer.
             if let Some([w, h]) = app.session.project.item(ItemId(*item)).and_then(|it| frame_size(&it.kind, ectx.comp.pixel_aspect)) {
@@ -55,7 +60,7 @@ pub(crate) fn show(app: &mut EffectcraftApp, ui: &egui::Ui, painter: &egui::Pain
         DragPayload::Property { .. } => vec![],
     };
     // Layer drops outline the target layer; the others outline the whole viewer.
-    let layer_drop = matches!(payload.as_ref(), DragPayload::Effect(_) | DragPayload::Preset { .. });
+    let layer_drop = alt_item || matches!(payload.as_ref(), DragPayload::Effect(_) | DragPayload::Preset { .. });
     if !layer_drop && !actions.is_empty() {
         painter.rect_stroke(map.area, 0.0, stroke, StrokeKind::Inside);
     }
@@ -80,3 +85,21 @@ fn frame_size(kind: &ItemKind, comp_pixel_aspect: f64) -> Option<[f32; 2]> {
     let stretch = if comp_pixel_aspect > 0.0 && pixel_aspect > 0.0 { pixel_aspect / comp_pixel_aspect } else { 1.0 };
     (w > 0 && h > 0).then_some([(w as f64 * stretch) as f32, h as f32])
 }
+
+/// The `layer.replaceSource` for an Alt/Option-drop of Project item `item` at comp point `at`: the
+/// topmost layer there, outlined, if it can take the item as its source (a locked one cannot).
+fn alt_replace(
+    app: &EffectcraftApp,
+    ectx: &EvalCtx,
+    painter: &egui::Painter,
+    map: &ViewerMap,
+    stroke: Stroke,
+    at: [f64; 2],
+    item: u64,
+) -> Option<(&'static str, Value)> {
+    let layer = layer_at_including_locked(ectx, at).filter(|l| super::timeline::replace_source_target(app, ectx.comp_id, ItemId(item), l.id, ectx.comp))?;
+    if let Some((_, q, _)) = layer_quad(ectx, layer) {
+        painter.add(egui::Shape::closed_line(q.iter().map(|c| map.to_screen(*c)).collect(), stroke));
+    }
+    Some(("layer.replaceSource", json!({"layers": [layer.id.0], "item": item, "fixExpressions": false})))
+}
diff --git a/crates/ui-egui/src/theme.rs b/crates/ui-egui/src/theme.rs
index 227866bcc..aa1b30350 100644
--- a/crates/ui-egui/src/theme.rs
+++ b/crates/ui-egui/src/theme.rs
@@ -129,6 +129,16 @@ impl Tokens {
     pub fn grad_top(&self, c: Color32) -> Color32 {
         if self.gradients { c.lerp_to_gamma(Color32::WHITE, 0.06) } else { c }
     }
+
+    /// The tokens a property's value fields use (#1306): with an expression driving the property
+    /// (`expression`, [`Property::has_expression`]) its values show in the expression colour, red
+    /// as in After Effects, hovered and dragged too; otherwise these tokens. For the values only:
+    /// the name, stopwatch and swatches keep the ordinary tokens.
+    ///
+    /// [`Property::has_expression`]: effectcraft_engine::project::Property::has_expression
+    pub fn for_value(self, expression: bool) -> Tokens {
+        if expression { Tokens { hot_text: self.expr_text, accent_hover: self.expr_text, ..self } } else { self }
+    }
 }
 
 impl Tokens {
diff --git a/crates/ui-egui/tests/it/main.rs b/crates/ui-egui/tests/it/main.rs
index 1dcf02da0..54f641687 100644
--- a/crates/ui-egui/tests/it/main.rs
+++ b/crates/ui-egui/tests/it/main.rs
@@ -8,6 +8,7 @@ mod ui_agent_audit;
 mod ui_angles;
 mod ui_audio_scrub;
 mod ui_azerty_shortcuts;
+mod ui_batch_links;
 mod ui_batch_switches;
 mod ui_blank_context_menus;
 mod ui_camera_tracker;
@@ -20,6 +21,7 @@ mod ui_drag_drop;
 mod ui_effect_controls;
 mod ui_effect_drop_highlight;
 mod ui_effect_names;
+mod ui_expression_values;
 mod ui_font_search;
 mod ui_form_fit;
 mod ui_frame_step;
@@ -80,6 +82,7 @@ mod ui_tracker;
 mod ui_unreadable_footage;
 mod ui_video_preview_off;
 mod ui_viewer;
+mod ui_viewer_trackpad;
 mod ui_viewers;
 mod ui_visual_review;
 mod ui_web_gpu_storage;
diff --git a/crates/ui-egui/tests/it/ui_batch_links.rs b/crates/ui-egui/tests/it/ui_batch_links.rs
new file mode 100644
index 000000000..5b2cea090
--- /dev/null
+++ b/crates/ui-egui/tests/it/ui_batch_links.rs
@@ -0,0 +1,209 @@
+//! Parent and Track Matte for several layers at once (#1260): on a selected layer's row, the
+//! Timeline's Parent and Track Matte menus and pick whips set every selected layer; on an
+//! unselected row, that layer alone. One undo step each; each layer keeps its own matte mode.
+
+use effectcraft_engine::Session;
+use effectcraft_engine::project::{LayerId, MatteKind};
+use effectcraft_ui_egui::EffectcraftApp;
+use egui::{Event, Modifiers, PointerButton, Pos2, Rect, pos2, vec2};
+use egui_kittest::Harness;
+use egui_kittest::kittest::Queryable as _;
+use serde_json::json;
+
+/// Solids A, B, C, P (moved and scaled, a parent) and the mattes X and Y; stacked Y, X, P, C, B, A
+/// from the top. The Track Matte column is shown.
+fn harness() -> (Harness<'static, EffectcraftApp>, [u64; 6]) {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Links", "width": 320, "height": 180, "duration": 4})).unwrap();
+    let ids = ["A", "B", "C", "P", "X", "Y"]
+        .map(|n| s.execute("layer.newSolid", json!({"name": n, "color": "#406080", "width": 40, "height": 40})).unwrap()["layer"].as_u64().unwrap());
+    s.execute("prop.set", json!({"layer": ids[3], "path": "transform/position", "value": [60, 40]})).unwrap();
+    s.execute("prop.set", json!({"layer": ids[3], "path": "transform/scale", "value": [50, 50]})).unwrap();
+    s.history.undo.clear();
+    let mut h = Harness::builder().with_size(vec2(1600.0, 1000.0)).build_eframe(|_| EffectcraftApp::new(s));
+    h.state_mut().ui.timeline.show_modes = true;
+    h.state_mut().ui.timeline.columns_w = 900.0;
+    h.run_steps(3);
+    (h, ids)
+}
+
+fn rect(h: &Harness<'_, EffectcraftApp>, id: &str) -> Rect {
+    let e = h.state().auto.find(id).unwrap_or_else(|| panic!("no {id}"));
+    Rect::from_min_size(pos2(e.rect[0], e.rect[1]), vec2(e.rect[2], e.rect[3]))
+}
+
+fn press(h: &mut Harness<'_, EffectcraftApp>, at: Pos2, pressed: bool) {
+    h.event(Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers: Modifiers::NONE });
+}
+
+fn click(h: &mut Harness<'_, EffectcraftApp>, at: Pos2) {
+    h.event(Event::PointerMoved(at));
+    h.step();
+    press(h, at, true);
+    h.step();
+    press(h, at, false);
+    h.run_steps(3);
+}
+
+/// Open the menu at automation id `dropdown` and choose `item` in it.
+fn choose(h: &mut Harness<'_, EffectcraftApp>, dropdown: &str, item: &str) {
+    let menu = rect(h, dropdown);
+    // Other rows' menus show their choice as well ("No Track Matte"): the entry is a node the
+    // opened menu added.
+    let shown: Vec<Rect> = h.query_all_by_label(item).map(|n| n.rect()).collect();
+    click(h, menu.center());
+    // (The menu may open above it to fit the window: the entry nearest to it.)
+    let off = |r: &Rect| (r.center().y - menu.center().y).abs();
+    let at = h.query_all_by_label(item).map(|n| n.rect()).filter(|r| !shown.contains(r)).min_by(|a, b| off(a).total_cmp(&off(b)));
+    let at = at.unwrap_or_else(|| panic!("no {item} in the {dropdown} menu")).center();
+    click(h, at);
+}
+
+/// Drag the pick whip `whip` onto layer `onto`'s row.
+fn whip(h: &mut Harness<'_, EffectcraftApp>, whip: &str, onto: u64) {
+    let (from, to) = (rect(h, whip).center(), rect(h, &format!("timeline.layer.{onto}.row")).center());
+    h.event(Event::PointerMoved(from));
+    h.step();
+    press(h, from, true);
+    h.step();
+    for i in 1..=10 {
+        h.event(Event::PointerMoved(from + (to - from) * (i as f32 / 10.0)));
+        h.step();
+    }
+    press(h, to, false);
+    h.run_steps(3);
+}
+
+fn select(h: &mut Harness<'_, EffectcraftApp>, ids: &[u64]) {
+    h.state_mut().session.execute("layer.select", json!({"layers": ids})).unwrap();
+    h.run_steps(2);
+}
+
+fn parent(h: &Harness<'_, EffectcraftApp>, id: u64) -> Option<u64> {
+    h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().parent.map(|p| p.0)
+}
+
+fn position(h: &Harness<'_, EffectcraftApp>, id: u64) -> [f64; 3] {
+    h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().props.prop("transform/position").unwrap().value.as_vec3()
+}
+
+fn matte(h: &Harness<'_, EffectcraftApp>, id: u64) -> Option<(u64, MatteKind)> {
+    h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().track_matte.map(|m| (m.layer.0, m.kind))
+}
+
+/// The project and its undo steps as they are now, to compare with after an undo or a refusal.
+fn mark(h: &Harness<'_, EffectcraftApp>) -> (std::sync::Arc<effectcraft_engine::project::Project>, usize) {
+    (h.state().session.project.clone(), h.state().session.history.undo.len())
+}
+
+fn unchanged(h: &Harness<'_, EffectcraftApp>, m: &(std::sync::Arc<effectcraft_engine::project::Project>, usize)) -> bool {
+    h.state().session.project.same_content(&m.0) && h.state().session.history.undo.len() == m.1
+}
+
+#[test]
+fn parent_menu_and_pick_whip_parent_the_selected_layers() {
+    let (mut h, [a, b, c, p, ..]) = harness();
+    let start = position(&h, a);
+    select(&mut h, &[a, b]);
+    let before = mark(&h);
+    // The Parent menu on A's (selected) row parents A and B, kept where they are.
+    choose(&mut h, &format!("timeline.layer.{a}.parent"), "3. P");
+    assert_eq!([parent(&h, a), parent(&h, b), parent(&h, c)], [Some(p), Some(p), None]);
+    assert!(position(&h, a) != start && position(&h, a) == position(&h, b), "both re-expressed in P's space");
+    assert_eq!(h.state().session.history.undo.len(), before.1 + 1, "one undo step");
+    h.state_mut().session.execute("edit.undo", json!({})).unwrap();
+    h.run_steps(2);
+    assert!(unchanged(&h, &before), "one undo puts both back");
+    // The pick whip of an unselected row parents that layer alone.
+    whip(&mut h, &format!("timeline.layer.{c}.pickWhip"), p);
+    assert_eq!([parent(&h, a), parent(&h, b), parent(&h, c)], [None, None, Some(p)]);
+    // A selected row's whip parents the selection, less the parent itself if selected.
+    select(&mut h, &[a, b, p]);
+    whip(&mut h, &format!("timeline.layer.{a}.pickWhip"), p);
+    assert_eq!([parent(&h, a), parent(&h, b), parent(&h, p)], [Some(p), Some(p), None]);
+    // A cycle (P under A, while A is under P) is refused as a whole.
+    select(&mut h, &[p, c]);
+    let before = mark(&h);
+    choose(&mut h, &format!("timeline.layer.{p}.parent"), "6. A");
+    assert!(unchanged(&h, &before), "the refused parenting changed nothing");
+    assert_eq!([parent(&h, p), parent(&h, c)], [None, Some(p)]);
+}
+
+#[test]
+fn track_matte_menu_and_pick_whip_set_the_selected_layers_mattes() {
+    let (mut h, [a, b, c, _, x, y]) = harness();
+    h.state_mut().session.execute("layer.setTrackMatte", json!({"layer": a, "matte": x, "kind": "luma"})).unwrap();
+    h.state_mut().session.execute("layer.setTrackMatte", json!({"layer": b, "matte": x, "kind": "alpha"})).unwrap();
+    select(&mut h, &[a, b]);
+    let before = mark(&h);
+    // A new matte layer for both; each keeps its mode; C (not selected) keeps none.
+    choose(&mut h, &format!("timeline.layer.{a}.trackMatte"), "1. Y");
+    assert_eq!([matte(&h, a), matte(&h, b), matte(&h, c)], [Some((y, MatteKind::Luma)), Some((y, MatteKind::Alpha)), None]);
+    assert!(!h.state().session.active_comp().unwrap().layer(LayerId(y)).unwrap().switches.video, "Y is hidden as a matte");
+    h.state_mut().session.execute("edit.undo", json!({})).unwrap();
+    h.run_steps(2);
+    assert!(unchanged(&h, &before), "one undo puts both mattes and Y's visibility back");
+    // A mode for both, then No Track Matte for both.
+    choose(&mut h, &format!("timeline.layer.{b}.trackMatte"), "Luma Inverted Matte");
+    assert_eq!([matte(&h, a), matte(&h, b)], [Some((x, MatteKind::LumaInverted)), Some((x, MatteKind::LumaInverted))]);
+    choose(&mut h, &format!("timeline.layer.{a}.trackMatte"), "No Track Matte");
+    assert_eq!([matte(&h, a), matte(&h, b)], [None, None]);
+    // The track matte pick whip: a selected row's sets the selection's, an unselected row's
+    // its own.
+    whip(&mut h, &format!("timeline.layer.{a}.trackMattePickWhip"), y);
+    assert_eq!([matte(&h, a), matte(&h, b), matte(&h, c)], [Some((y, MatteKind::Alpha)), Some((y, MatteKind::Alpha)), None]);
+    whip(&mut h, &format!("timeline.layer.{c}.trackMattePickWhip"), x);
+    assert_eq!([matte(&h, a), matte(&h, c)], [Some((y, MatteKind::Alpha)), Some((x, MatteKind::Alpha))]);
+}
+
+fn video(h: &Harness<'_, EffectcraftApp>, id: u64) -> bool {
+    h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().switches.video
+}
+
+/// A locked layer in the selection stays selected, and keeps its parent, its transform and its
+/// matte while another selected row's menus and pick whips change the rest.
+#[test]
+fn locked_selected_layers_keep_their_parent_and_matte() {
+    let (mut h, [a, b, c, _, x, _]) = harness();
+    select(&mut h, &[a, b]);
+    // B alone (a click on its Lock switch locks the whole selection).
+    h.state_mut().session.execute("layer.setSwitch", json!({"layers": [b], "switch": "lock", "value": true})).unwrap();
+    h.run_steps(2);
+    let selected: Vec<u64> = h.state().session.state.selected_layers.iter().map(|l| l.0).collect();
+    assert!(h.state().session.active_comp().unwrap().layer(LayerId(b)).unwrap().switches.locked && selected == vec![a, b], "{selected:?}");
+    let b_position = position(&h, b);
+    choose(&mut h, &format!("timeline.layer.{a}.parent"), "3. P");
+    whip(&mut h, &format!("timeline.layer.{a}.pickWhip"), c);
+    choose(&mut h, &format!("timeline.layer.{a}.trackMatte"), "1. Y");
+    whip(&mut h, &format!("timeline.layer.{a}.trackMattePickWhip"), x);
+    assert_eq!((parent(&h, a), matte(&h, a)), (Some(c), Some((x, MatteKind::Alpha))), "A changed each time");
+    assert_eq!((parent(&h, b), matte(&h, b), position(&h, b)), (None, None, b_position), "locked B didn't");
+}
+
+/// Selected nulls (no Track Matte on their rows) get no matte from another row's menu or pick
+/// whip: at the top of the comp one used to refuse the whole mode change (nothing above it to
+/// take as a matte), at the bottom it took the layer above as its matte and hid it.
+#[test]
+fn selected_nulls_get_no_matte() {
+    let (mut h, [a, b, _, _, x, y]) = harness();
+    h.state_mut().session.execute("layer.setTrackMatte", json!({"layers": [a, b], "matte": x, "kind": "alpha"})).unwrap();
+    let n = h.state_mut().session.execute("layer.newNull", json!({"name": "N"})).unwrap()["layer"].as_u64().unwrap();
+    select(&mut h, &[a, b, n]);
+    choose(&mut h, &format!("timeline.layer.{a}.trackMatte"), "Luma Matte");
+    assert_eq!([matte(&h, a), matte(&h, b), matte(&h, n)], [Some((x, MatteKind::Luma)), Some((x, MatteKind::Luma)), None], "a null on top");
+    h.state_mut().session.execute("layer.arrange", json!({"layers": [n], "to": "back"})).unwrap();
+    select(&mut h, &[a, b, n]);
+    choose(&mut h, &format!("timeline.layer.{a}.trackMatte"), "Alpha Inverted Matte");
+    assert_eq!(
+        [matte(&h, a), matte(&h, b), matte(&h, n)],
+        [Some((x, MatteKind::AlphaInverted)), Some((x, MatteKind::AlphaInverted)), None],
+        "a null at the bottom"
+    );
+    assert!(video(&h, a), "A wasn't hidden as the null's matte");
+    whip(&mut h, &format!("timeline.layer.{a}.trackMattePickWhip"), y);
+    assert_eq!(
+        [matte(&h, a), matte(&h, b), matte(&h, n)],
+        [Some((y, MatteKind::AlphaInverted)), Some((y, MatteKind::AlphaInverted)), None],
+        "the pick whip too"
+    );
+}
diff --git a/crates/ui-egui/tests/it/ui_camera_tracker.rs b/crates/ui-egui/tests/it/ui_camera_tracker.rs
index 2ab27fd6e..f7d349342 100644
--- a/crates/ui-egui/tests/it/ui_camera_tracker.rs
+++ b/crates/ui-egui/tests/it/ui_camera_tracker.rs
@@ -171,8 +171,8 @@ fn viewer_zooms_and_pans_over_the_track_points() {
     let zoom = h.state().ui.viewer.zoom;
     h.input_mut().events.push(egui::Event::PointerMoved(at));
     h.input_mut().events.push(egui::Event::MouseWheel {
-        unit: egui::MouseWheelUnit::Point,
-        delta: egui::vec2(0.0, 120.0),
+        unit: egui::MouseWheelUnit::Line,
+        delta: egui::vec2(0.0, 3.0),
         modifiers: Default::default(),
         phase: egui::TouchPhase::Move,
         source: egui::MouseWheelSource::Wheel,
diff --git a/crates/ui-egui/tests/it/ui_comp_presets.rs b/crates/ui-egui/tests/it/ui_comp_presets.rs
index 0b0b30720..9e71f8fd7 100644
--- a/crates/ui-egui/tests/it/ui_comp_presets.rs
+++ b/crates/ui-egui/tests/it/ui_comp_presets.rs
@@ -83,3 +83,23 @@ fn a_preset_name_cannot_be_a_built_in_one() {
     assert!(h.state().auto.find("dialog.comp.presetName").is_none());
     assert!(preset_names(&h).is_empty());
 }
+
+/// Cancel and OK stay where they are when switching between Basic, Advanced and 3D Renderer,
+/// at any interface scale: the tabs' heights are measured, not assumed.
+#[test]
+fn composition_settings_buttons_stay_put_between_tabs() {
+    for zoom in [1.0, 1.3] {
+        let mut h = harness();
+        h.ctx.set_zoom_factor(zoom);
+        h.run_steps(3);
+        open_settings(&mut h);
+        let rects = |h: &Harness<'_, EffectcraftApp>| {
+            ["dialog.comp.ok", "dialog.comp.cancel", "dialog.comp.name"].map(|id| h.state().auto.find(id).unwrap_or_else(|| panic!("no {id}")).rect)
+        };
+        let basic = rects(&h);
+        for tab in ["advanced", "renderer", "basic"] {
+            click(&mut h, &format!("dialog.comp.tab.{tab}"));
+            assert_eq!(rects(&h), basic, "{tab} at {zoom}x");
+        }
+    }
+}
diff --git a/crates/ui-egui/tests/it/ui_drag_drop.rs b/crates/ui-egui/tests/it/ui_drag_drop.rs
index e405bf777..ec8db35cc 100644
--- a/crates/ui-egui/tests/it/ui_drag_drop.rs
+++ b/crates/ui-egui/tests/it/ui_drag_drop.rs
@@ -124,6 +124,44 @@ fn alt_dragging_a_project_item_replaces_the_layer_source() {
     assert_eq!(layer.name, "Top", "the layer keeps its name");
 }
 
+/// Alt/Option-dropping a Project item on the Composition viewer replaces the source of the layer
+/// under the pointer, as in the Timeline, instead of adding a layer (#2173).
+#[test]
+fn alt_dropping_a_project_item_on_the_viewer_replaces_the_layer_source() {
+    use effectcraft_engine::project::{ItemId, LayerId, LayerSource};
+    let (mut h, clip) = harness();
+    let item = rect(&h, &format!("project.item.{clip}.name")).center();
+    let to = comp_to_screen(&h.ctx, [160.0, 90.0]).unwrap();
+    // The three solids overlap completely, so the topmost one is under the pointer.
+    let (top, middle, bottom) = (layer_id(&h, "Top"), layer_id(&h, "Middle"), layer_id(&h, "Bottom"));
+    let source = |h: &Harness<'_, EffectcraftApp>, id: u64| h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().source.clone();
+    let (middle_before, bottom_before) = (source(&h, middle), source(&h, bottom));
+    let before = stack(&h);
+    drag(&mut h, item, to, Modifiers::ALT);
+    assert_eq!(stack(&h), before, "no layer is added");
+    assert_eq!(source(&h, top), LayerSource::Comp { item: ItemId(clip) }, "the layer under the pointer takes the new source");
+    assert_eq!(source(&h, middle), middle_before, "the layer below it keeps its source");
+    assert_eq!(source(&h, bottom), bottom_before, "the bottom layer keeps its source");
+}
+
+/// A locked layer under the pointer refuses the Alt-drop; the layer behind it is not replaced
+/// instead (#2173).
+#[test]
+fn alt_dropping_on_a_locked_layer_in_the_viewer_replaces_nothing() {
+    use effectcraft_engine::project::LayerId;
+    let (mut h, clip) = harness();
+    let item = rect(&h, &format!("project.item.{clip}.name")).center();
+    let to = comp_to_screen(&h.ctx, [160.0, 90.0]).unwrap();
+    let top = layer_id(&h, "Top");
+    h.state_mut().session.execute("layer.setSwitch", json!({"layers": [top], "switch": "locked", "value": true})).unwrap();
+    h.run_steps(3);
+    let sources = |h: &Harness<'_, EffectcraftApp>| h.state().session.active_comp().unwrap().layers.iter().map(|l| l.source.clone()).collect::<Vec<_>>();
+    let before = sources(&h);
+    drag(&mut h, item, to, Modifiers::ALT);
+    assert_eq!(sources(&h), before, "no layer takes the new source");
+    assert!(h.state().session.active_comp().unwrap().layer(LayerId(top)).unwrap().switches.locked);
+}
+
 /// Ctrl+Alt+/ (Cmd+Opt+/ on macOS) replaces every selected layer's source with the Project panel
 /// selection (#991).
 #[test]
diff --git a/crates/ui-egui/tests/it/ui_expression_values.rs b/crates/ui-egui/tests/it/ui_expression_values.rs
new file mode 100644
index 000000000..b797e6cf6
--- /dev/null
+++ b/crates/ui-egui/tests/it/ui_expression_values.rs
@@ -0,0 +1,296 @@
+//! #1306 (from #1072): a property driven by an expression shows its value in red, the expression
+//! colour, in the Timeline, Effect Controls and the Properties panel, as in After Effects: scalars,
+//! every part of a vector (with its separator) and both parts of an angle (with its sign), hovered
+//! and dragged too, in dark and light themes. A disabled, removed or empty expression shows the
+//! ordinary colour again. The tests read the colour the value text is painted with (the frame's
+//! text shapes: the numbers are painted with an override colour, the separator and sign as plain
+//! text), and require every expected part to be there.
+
+use effectcraft_engine::Session;
+use effectcraft_engine::project::{LayerId, PropGroup};
+use effectcraft_ui_egui::EffectcraftApp;
+use effectcraft_ui_egui::dock::PanelKind;
+use effectcraft_ui_egui::theme::ThemeKind;
+use egui::epaint::Shape;
+use egui::{Color32, Event, Modifiers, PointerButton, Pos2, Rect, pos2, vec2};
+use egui_kittest::Harness;
+use serde_json::json;
+
+const TIMELINE: &str = "timeline.prop";
+const EFFECT_CONTROLS: &str = "effectControls.prop";
+const PROPERTIES: &str = "properties.prop";
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+enum Kind {
+    /// Two components (X, Y).
+    Vector,
+    /// Revolutions, sign and degrees.
+    Angle,
+    Scalar,
+}
+
+/// A property whose value the tests check, and the panels that must show it.
+#[derive(Clone, Copy, Debug)]
+struct Checked {
+    uid: u64,
+    kind: Kind,
+    panels: &'static [&'static str],
+}
+
+/// A comp with one solid and the Transform effect on it.
+struct Ids {
+    layer: u64,
+    /// Transform Position, Rotation and Opacity (Timeline and Properties panel), and the Transform
+    /// effect's Position, Rotation and Opacity (Effect Controls).
+    driven: [Checked; 6],
+    /// Transform Scale: no expression.
+    scale: Checked,
+}
+
+fn setup() -> (Harness<'static, EffectcraftApp>, Ids) {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "E", "width": 320, "height": 180, "duration": 4})).unwrap();
+    let l = s.execute("layer.newSolid", json!({"color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    let fx = s.execute("effect.apply", json!({"layers": [l], "effect": "Transform"})).unwrap()["effects"][0].as_u64().unwrap();
+    let layer = s.active_comp().unwrap().layer(LayerId(l)).unwrap().clone();
+    let uid = |path: &str| layer.props.prop(path).unwrap_or_else(|| panic!("no {path}")).uid;
+    let g: &PropGroup = layer.props.find_group(fx).unwrap();
+    let fuid = |m: &str| g.get(m).unwrap_or_else(|| panic!("no effect {m}")).uid;
+    const LAYER: &[&str] = &[TIMELINE, PROPERTIES];
+    const EFFECT: &[&str] = &[EFFECT_CONTROLS];
+    let c = |uid, kind, panels| Checked { uid, kind, panels };
+    let ids = Ids {
+        layer: l,
+        driven: [
+            c(uid("transform/position"), Kind::Vector, LAYER),
+            c(uid("transform/rotation"), Kind::Angle, LAYER),
+            c(uid("transform/opacity"), Kind::Scalar, LAYER),
+            c(fuid("position"), Kind::Vector, EFFECT),
+            c(fuid("rotation"), Kind::Angle, EFFECT),
+            c(fuid("opacity"), Kind::Scalar, EFFECT),
+        ],
+        scale: c(uid("transform/scale"), Kind::Vector, LAYER),
+    };
+    let transform = layer.props.sub("transform").unwrap().uid;
+    s.state.selected_layers = vec![LayerId(l)];
+    let mut app = EffectcraftApp::new(s);
+    app.show_panel(PanelKind::EffectControls);
+    app.ui.timeline.open_layers.insert(l);
+    app.ui.timeline.open_groups.insert(transform);
+    let mut h = Harness::builder().with_size(vec2(1600.0, 1000.0)).build_eframe(|_| app);
+    h.run_steps(4);
+    (h, ids)
+}
+
+fn set_expression(h: &mut Harness<'_, EffectcraftApp>, ids: &Ids, prop: u64, p: &serde_json::Value) {
+    let mut p = p.clone();
+    p["layer"] = json!(ids.layer);
+    p["prop"] = json!(prop);
+    h.state_mut().session.execute("prop.setExpression", p).unwrap();
+}
+
+fn set_theme(h: &mut Harness<'_, EffectcraftApp>, theme: ThemeKind) {
+    let ctx = h.ctx.clone();
+    h.state_mut().set_theme(&ctx, theme);
+    h.run_steps(3);
+}
+
+fn rect_of(h: &Harness<'_, EffectcraftApp>, id: &str) -> Rect {
+    let e = h.state().auto.find(id).unwrap_or_else(|| panic!("no {id}: the part isn't shown"));
+    Rect::from_min_size(pos2(e.rect[0], e.rect[1]), vec2(e.rect[2], e.rect[3]))
+}
+
+/// The area of `c`'s value in `panel`, every expected part required: both components of a vector,
+/// the revolutions and degrees of an angle (the separator and sign lie between them).
+fn value_area(h: &Harness<'_, EffectcraftApp>, panel: &str, c: Checked) -> Rect {
+    let uid = c.uid;
+    match c.kind {
+        Kind::Vector => rect_of(h, &format!("{panel}.{uid}.value.0")).union(rect_of(h, &format!("{panel}.{uid}.value.1"))),
+        Kind::Angle => rect_of(h, &format!("{panel}.{uid}.revolutions")).union(rect_of(h, &format!("{panel}.{uid}.value"))),
+        Kind::Scalar => rect_of(h, &format!("{panel}.{uid}.value")),
+    }
+}
+
+/// The text painted inside `area` in the last frame, with its colour.
+fn texts(h: &Harness<'_, EffectcraftApp>, area: Rect) -> Vec<(String, Color32)> {
+    fn walk(s: &Shape, area: Rect, out: &mut Vec<(String, Color32)>) {
+        match s {
+            Shape::Vec(v) => v.iter().for_each(|s| walk(s, area, out)),
+            Shape::Text(t) if area.expand(1.0).contains_rect(t.visual_bounding_rect()) && !t.galley.text().trim().is_empty() => {
+                out.push((t.galley.text().trim().to_string(), t.override_text_color.unwrap_or(t.fallback_color)));
+            }
+            _ => {}
+        }
+    }
+    let mut out = vec![];
+    for c in &h.output().shapes {
+        walk(&c.shape, area, &mut out);
+    }
+    out
+}
+
+/// `c`'s value in `panel` shows every part, all in `want`: two numbers and (in the Timeline) the
+/// `,` of a vector, the revolutions, sign and degrees of an angle, the number of a scalar.
+fn assert_value(h: &Harness<'_, EffectcraftApp>, panel: &str, c: Checked, want: Color32, what: &str) {
+    let shown = texts(h, value_area(h, panel, c));
+    let numbers = shown.iter().filter(|(s, _)| s.chars().any(|ch| ch.is_ascii_digit())).count();
+    let has = |text: &str| shown.iter().any(|(s, _)| s == text);
+    let ctx = format!("{what}: {:?} @{} in {panel}: {shown:?}", c.kind, c.uid);
+    match c.kind {
+        Kind::Vector => {
+            assert!(numbers >= 2, "{ctx}: both components");
+            if panel == TIMELINE {
+                assert!(has(","), "{ctx}: the separator");
+            }
+        }
+        Kind::Angle => {
+            assert!(numbers >= 2, "{ctx}: revolutions and degrees");
+            assert!(has("+") || has("-"), "{ctx}: the sign");
+        }
+        Kind::Scalar => assert!(numbers >= 1, "{ctx}: the number"),
+    }
+    assert!(shown.iter().all(|(_, col)| *col == want), "{ctx}: want {want:?}");
+}
+
+/// Every checked property in every panel it belongs to.
+fn assert_all(h: &Harness<'_, EffectcraftApp>, checked: &[Checked], want: Color32, what: &str) {
+    for c in checked {
+        for panel in c.panels {
+            assert_value(h, panel, *c, want, what);
+        }
+    }
+}
+
+/// Expression-driven values are red in every panel, in both themes; Scale (none) stays blue.
+#[test]
+fn expression_driven_values_are_red_in_every_panel() {
+    let (mut h, ids) = setup();
+    for c in ids.driven {
+        set_expression(&mut h, &ids, c.uid, &json!({"expression": "value"}));
+    }
+    for theme in [ThemeKind::Dark, ThemeKind::Light] {
+        set_theme(&mut h, theme);
+        let t = h.state().tokens;
+        assert_ne!(t.expr_text, t.hot_text);
+        assert_all(&h, &ids.driven, t.expr_text, &format!("{theme:?} expression"));
+        assert_all(&h, &[ids.scale], t.hot_text, &format!("{theme:?} no expression"));
+    }
+}
+
+/// Disabled, removed or whitespace-only: the ordinary colour; enabled again: red. Every part of
+/// every value is checked again after each change, in both themes.
+#[test]
+fn expression_state_changes_switch_the_colour() {
+    let (mut h, ids) = setup();
+    let states = [
+        (json!({"expression": "value"}), true, "enabled"),
+        (json!({"enabled": false}), false, "disabled"),
+        (json!({"enabled": true}), true, "enabled again"),
+        (json!({"expression": ""}), false, "removed"),
+        (json!({"expression": "value"}), true, "set again"),
+        (json!({"expression": "   "}), false, "whitespace only"),
+    ];
+    for theme in [ThemeKind::Dark, ThemeKind::Light] {
+        set_theme(&mut h, theme);
+        let t = h.state().tokens;
+        for (p, red, what) in &states {
+            for c in ids.driven {
+                set_expression(&mut h, &ids, c.uid, p);
+            }
+            h.run_steps(3);
+            let want = if *red { t.expr_text } else { t.hot_text };
+            assert_all(&h, &ids.driven, want, &format!("{theme:?} {what}"));
+            assert_all(&h, &[ids.scale], t.hot_text, &format!("{theme:?} {what}: Scale"));
+        }
+    }
+}
+
+fn hover(h: &mut Harness<'_, EffectcraftApp>, at: Pos2) {
+    h.input_mut().events.push(Event::PointerMoved(at));
+    h.run_steps(2);
+}
+
+/// Hovering a value (an ordinary one takes the hover accent) keeps an expression-driven one red,
+/// in every panel and both themes.
+#[test]
+fn a_hovered_expression_value_stays_red() {
+    let (mut h, ids) = setup();
+    let opacity = ids.driven.iter().filter(|c| c.kind == Kind::Scalar).copied().collect::<Vec<_>>();
+    for c in &opacity {
+        set_expression(&mut h, &ids, c.uid, &json!({"expression": "value"}));
+    }
+    h.run_steps(3);
+    for theme in [ThemeKind::Dark, ThemeKind::Light] {
+        set_theme(&mut h, theme);
+        let t = h.state().tokens;
+        for c in &opacity {
+            for panel in c.panels {
+                let area = value_area(&h, panel, *c);
+                hover(&mut h, area.center());
+                let at = h.ctx.input(|i| i.pointer.hover_pos());
+                assert!(at.is_some_and(|p| area.contains(p)), "{theme:?} {panel}: the pointer is over the value");
+                assert_value(&h, panel, *c, t.expr_text, &format!("{theme:?} hovered"));
+            }
+        }
+        // An ordinary value does take the hover accent.
+        let area = value_area(&h, TIMELINE, ids.scale);
+        let x = rect_of(&h, &format!("{TIMELINE}.{}.value.0", ids.scale.uid)).center();
+        hover(&mut h, x);
+        let shown = texts(&h, area);
+        assert!(shown.iter().any(|(_, c)| *c == t.accent_hover), "{theme:?} an ordinary hovered value: {shown:?}");
+        hover(&mut h, pos2(5.0, 5.0));
+    }
+}
+
+/// Dragging (scrubbing) an expression-driven value keeps it red while the drag is on, in the
+/// Timeline and Effect Controls.
+#[test]
+fn a_dragged_expression_value_stays_red() {
+    let (mut h, ids) = setup();
+    let opacity = ids.driven.iter().filter(|c| c.kind == Kind::Scalar).copied().collect::<Vec<_>>();
+    for c in &opacity {
+        set_expression(&mut h, &ids, c.uid, &json!({"expression": "value"}));
+    }
+    h.run_steps(3);
+    let t = h.state().tokens;
+    for (c, panel) in [(opacity[0], TIMELINE), (opacity[1], EFFECT_CONTROLS)] {
+        let at = value_area(&h, panel, c).center();
+        h.input_mut().events.push(Event::PointerMoved(at));
+        h.step();
+        h.input_mut().events.push(Event::PointerButton { pos: at, button: PointerButton::Primary, pressed: true, modifiers: Modifiers::NONE });
+        h.step();
+        for k in 1..=4 {
+            h.input_mut().events.push(Event::PointerMoved(at + vec2(3.0 * k as f32, 0.0)));
+            h.step();
+        }
+        assert!(h.ctx.dragged_id().is_some(), "{panel}: a drag is on");
+        assert_value(&h, panel, c, t.expr_text, &format!("{panel} dragged"));
+        let end = at + vec2(12.0, 0.0);
+        h.input_mut().events.push(Event::PointerButton { pos: end, button: PointerButton::Primary, pressed: false, modifiers: Modifiers::NONE });
+        h.run_steps(3);
+        hover(&mut h, pos2(5.0, 5.0));
+    }
+}
+
+/// Separate Dimensions: X Position and Y Position are separate scalars, so an expression on X Position
+/// turns only X red, in the Timeline and Properties panel and both themes; Y Position stays blue.
+#[test]
+fn separated_position_colours_each_dimension_on_its_own() {
+    let (mut h, ids) = setup();
+    h.state_mut().session.execute("prop.separateDimensions", json!({"layer": ids.layer, "value": true})).unwrap();
+    let uid = |h: &Harness<'_, EffectcraftApp>, path: &str| {
+        let s = &h.state().session;
+        s.active_comp().unwrap().layer(LayerId(ids.layer)).unwrap().props.prop(path).unwrap_or_else(|| panic!("no {path}")).uid
+    };
+    const LAYER: &[&str] = &[TIMELINE, PROPERTIES];
+    let x = Checked { uid: uid(&h, "transform/positionX"), kind: Kind::Scalar, panels: LAYER };
+    let y = Checked { uid: uid(&h, "transform/positionY"), kind: Kind::Scalar, panels: LAYER };
+    set_expression(&mut h, &ids, x.uid, &json!({"expression": "value"}));
+    h.run_steps(3);
+    for theme in [ThemeKind::Dark, ThemeKind::Light] {
+        set_theme(&mut h, theme);
+        let t = h.state().tokens;
+        assert_all(&h, &[x], t.expr_text, &format!("{theme:?} X Position (expression)"));
+        assert_all(&h, &[y], t.hot_text, &format!("{theme:?} Y Position (none)"));
+    }
+}
diff --git a/crates/ui-egui/tests/it/ui_layer_panel_zoom.rs b/crates/ui-egui/tests/it/ui_layer_panel_zoom.rs
index 1aabdd2bc..73ed95cbd 100644
--- a/crates/ui-egui/tests/it/ui_layer_panel_zoom.rs
+++ b/crates/ui-egui/tests/it/ui_layer_panel_zoom.rs
@@ -107,8 +107,8 @@ fn wheel_zooms_around_the_pointer_and_hand_tool_pans() {
     let at = canvas.min + canvas.size() * 0.25;
     h.input_mut().events.push(Event::PointerMoved(at));
     h.input_mut().events.push(Event::MouseWheel {
-        unit: egui::MouseWheelUnit::Point,
-        delta: vec2(0.0, 120.0),
+        unit: egui::MouseWheelUnit::Line,
+        delta: vec2(0.0, 3.0),
         modifiers: Default::default(),
         phase: egui::TouchPhase::Move,
         source: egui::MouseWheelSource::Wheel,
@@ -176,3 +176,33 @@ fn roto_brush_in_the_composition_panel_says_where_it_works() {
     assert_eq!(h.state().ui.layer_panel, Some(box_id(&h)));
     assert_eq!(h.state().ui.focused, PanelKind::Layer);
 }
+
+/// A two-finger trackpad scroll pans the layer with any tool and a pinch zooms around the pointer.
+#[test]
+fn trackpad_scroll_pans_and_pinch_zooms_around_the_pointer() {
+    let mut h = harness();
+    let canvas = rect(&h, "layerPanel.canvas");
+    let at = canvas.min + canvas.size() * 0.25;
+    h.input_mut().events.push(Event::PointerMoved(at));
+    h.input_mut().events.push(Event::MouseWheel {
+        unit: egui::MouseWheelUnit::Point,
+        delta: vec2(60.0, -30.0),
+        modifiers: Default::default(),
+        phase: egui::TouchPhase::Move,
+        source: egui::MouseWheelSource::Unknown,
+    });
+    h.run_steps(30);
+    let panned = rect(&h, "layerPanel.canvas");
+    let moved = panned.min - canvas.min;
+    assert!((moved.x - 60.0).abs() < 1.5 && (moved.y + 30.0).abs() < 1.5, "the scroll pans: {moved:?}");
+    assert!((panned.width() - canvas.width()).abs() < 0.5, "a scroll doesn't zoom: {} → {}", canvas.width(), panned.width());
+    // Pinch: zooms, keeping the point under the pointer.
+    let at = panned.min + panned.size() * 0.25;
+    h.input_mut().events.push(Event::PointerMoved(at));
+    h.input_mut().events.push(Event::Zoom(1.5));
+    h.run_steps(3);
+    let zoomed = rect(&h, "layerPanel.canvas");
+    assert!((zoomed.width() / panned.width() - 1.5).abs() < 0.01, "the pinch zooms: {} → {}", panned.width(), zoomed.width());
+    let still = zoomed.min + zoomed.size() * 0.25;
+    assert!(still.distance(at) < 2.0, "the point under the pointer stays put: {at:?} vs {still:?}");
+}
diff --git a/crates/ui-egui/tests/it/ui_menus.rs b/crates/ui-egui/tests/it/ui_menus.rs
index 38dcd15bc..424b75c48 100644
--- a/crates/ui-egui/tests/it/ui_menus.rs
+++ b/crates/ui-egui/tests/it/ui_menus.rs
@@ -65,6 +65,47 @@ fn shown(h: &Harness<'_, EffectcraftApp>, label: &str) -> bool {
     h.query_by_label_contains(label).is_some()
 }
 
+#[test]
+fn browse_presets_clears_search_and_scrolls_to_the_visible_presets_list() {
+    use effectcraft_ui_egui::dock::PanelKind;
+
+    let mut h = harness();
+    let ctx = h.ctx.clone();
+    let favorites: Vec<String> = effectcraft_engine::effects::all().iter().map(|effect| effect.id.to_string()).collect();
+    assert!(!favorites.is_empty(), "the test needs registered effects");
+    let recent: Vec<String> = favorites.iter().take(8).cloned().collect();
+
+    h.state_mut().session.prefs.effects_favorites = favorites;
+    h.state_mut().ui.effects_recent = recent;
+    h.state_mut().ui.effects_open.extend(["favorites".into(), "recent".into()]);
+    h.state_mut().ui.effects_search = "no matching animation preset".into();
+    h.state_mut().ui.effects_view.presets = true;
+
+    let managed = effectcraft_ui_egui::menus::invoke(h.state_mut(), &ctx, "effect.manage", json!({}));
+    assert!(managed.is_ok(), "{managed:?}");
+    assert_eq!(h.state().ui.focused, PanelKind::EffectsPresets);
+    assert_eq!(h.state().ui.effects_search, "no matching animation preset", "Manage Effects keeps its existing search behavior");
+    assert!(h.state().ui.effects_view.presets, "Manage Effects keeps the existing presets setting");
+
+    h.run_steps(3);
+    assert!(h.state().auto.find("effects.category.presets").is_none(), "the unmatched search hides Animation Presets");
+    h.state_mut().ui.effects_view.presets = false;
+
+    let result = effectcraft_ui_egui::menus::invoke(h.state_mut(), &ctx, "anim.browsePresets", json!({}));
+
+    assert!(result.is_ok(), "{result:?}");
+    assert_eq!(h.state().ui.focused, PanelKind::EffectsPresets);
+    assert!(h.state().ui.effects_search.is_empty());
+    assert!(h.state().ui.effects_view.presets);
+    assert!(h.state().ui.effects_open.contains("presets"));
+
+    h.run_steps(3);
+    assert!(
+        h.state().auto.find("effects.category.presets").is_some(),
+        "Animation Presets must be visible after Browse Presets, even below expanded Favorites and Recently Used"
+    );
+}
+
 /// Space (or any shortcut) while a menu is open goes to the menu, not the app: it started the
 /// preview behind the open menu.
 #[test]
diff --git a/crates/ui-egui/tests/it/ui_project_delete.rs b/crates/ui-egui/tests/it/ui_project_delete.rs
index f217c29db..2a395cf4b 100644
--- a/crates/ui-egui/tests/it/ui_project_delete.rs
+++ b/crates/ui-egui/tests/it/ui_project_delete.rs
@@ -364,3 +364,29 @@ fn a_cut_is_read_with_the_modifiers_where_it_is_in_the_frame() {
         assert_eq!(h.state().session.project.item(solid).is_none(), deletes, "case {n}: {events:?} after {before:?}");
     }
 }
+
+/// An open text edit stands down the Project-panel Clear redirect: the composition being typed
+/// into must not be deleted out from under it, with no confirmation when nothing uses it (#2227).
+#[test]
+fn clear_with_the_project_focused_stands_down_during_a_text_edit() {
+    let (mut h, _, _) = harness();
+    let working = h.state().session.active_comp_id().unwrap();
+    // the composition being typed into is also the Project panel's selection, as when it was opened
+    click(&mut h, &format!("project.item.{}.name", working.0), Modifiers::NONE);
+    let text = h.state_mut().session.execute("layer.newText", json!({"text": "Title", "size": 80})).unwrap()["layer"].as_u64().unwrap();
+    h.state_mut().session.execute("text.edit", json!({"layer": text, "created": true})).unwrap();
+    h.state_mut().ui.focused = PanelKind::Project;
+    h.run_steps(2);
+    assert!(h.state().session.state.project_selection.contains(&working), "the comp is the project selection");
+    let project = h.state().session.project.clone();
+
+    // Edit > Clear (the menu, or the control channel) dispatches through `invoke`
+    let ctx = h.ctx.clone();
+    let cleared = effectcraft_ui_egui::menus::invoke(h.state_mut(), &ctx, "edit.clear", json!({}));
+    h.run_steps(3);
+
+    cleared.expect("Clear stands down during a text edit");
+    assert!(h.state().session.project.item(working).is_some(), "the composition being typed into survives");
+    assert_eq!(h.state().session.project, project, "nothing was deleted");
+    assert!(h.state().session.state.text_edit.is_some(), "the text edit stays open");
+}
diff --git a/crates/ui-egui/tests/it/ui_tabs.rs b/crates/ui-egui/tests/it/ui_tabs.rs
index 65b429f44..5fc3d8598 100644
--- a/crates/ui-egui/tests/it/ui_tabs.rs
+++ b/crates/ui-egui/tests/it/ui_tabs.rs
@@ -466,3 +466,31 @@ fn open_comps_are_tabs_in_the_timeline_row_and_the_rest_are_in_its_overflow_menu
     assert_eq!(open_comps(&h), comps);
     assert!(has(&h, &format!("panel.tab.Timeline.{hidden}")));
 }
+
+/// Whether `id` was registered in the last frame (not the one before).
+fn drawn(h: &Harness<'_, EffectcraftApp>, id: &str) -> bool {
+    h.state().auto.elements.iter().any(|e| e.id == id)
+}
+
+#[test]
+fn an_inactive_comp_tab_shows_its_close_button_on_hover_and_closes_without_showing_its_comp() {
+    let (mut h, pre, main) = harness();
+    h.state_mut().session.state.open_comps = vec![ItemId(main), ItemId(pre)];
+    h.run_steps(3);
+    let (tm, tp) = (rect(&h, &format!("panel.tab.Timeline.{main}")), rect(&h, &format!("panel.tab.Timeline.{pre}")));
+    // The shown comp's × is always there; Pre's only while the pointer is over its tab.
+    h.event(Event::PointerMoved(pos2(800.0, 900.0)));
+    h.run_steps(2);
+    assert!(drawn(&h, "panel.tab.Timeline.close") && drawn(&h, &format!("panel.tab.Timeline.{main}.close")));
+    assert!(!drawn(&h, &format!("panel.tab.Timeline.{pre}.close")), "no × on an inactive tab the pointer is not over");
+    h.event(Event::PointerMoved(tp.center()));
+    h.run_steps(2);
+    let close = rect(&h, &format!("panel.tab.Timeline.{pre}.close"));
+    assert!(tp.contains_rect(close), "{close:?} inside {tp:?}");
+    // Every comp tab keeps the ×'s room: hovering changes no width.
+    assert_eq!((rect(&h, &format!("panel.tab.Timeline.{main}")), rect(&h, &format!("panel.tab.Timeline.{pre}"))), (tm, tp));
+    // Its × closes Pre's Timeline; Main stays shown.
+    click_n(&mut h, close.center(), 1);
+    assert_eq!(open_comps(&h), vec![main]);
+    assert_eq!(h.state().session.state.active_comp, Some(ItemId(main)));
+}
diff --git a/crates/ui-egui/tests/it/ui_text_edit.rs b/crates/ui-egui/tests/it/ui_text_edit.rs
index 84a218466..ea4b56d26 100644
--- a/crates/ui-egui/tests/it/ui_text_edit.rs
+++ b/crates/ui-egui/tests/it/ui_text_edit.rs
@@ -171,7 +171,7 @@ fn type_tool_click_type_edit_and_commit() {
 /// #831: clicking another panel (a solid's row in the Timeline) ends text editing and gives the
 /// keyboard back, whether the edit began with the Type tool (which stays selected) or by command:
 /// typed characters change no text and Space plays. The Character panel keeps the edit, and a
-/// text layer clicked into being and left empty goes away.
+/// text layer clicked into being and left empty stays, as it does in After Effects.
 #[test]
 fn clicking_another_panel_stops_typing_into_text() {
     for type_tool in [false, true] {
@@ -194,7 +194,7 @@ fn clicking_another_panel_stops_typing_into_text() {
             assert_eq!(layers(&h), 3, "the Type tool started a text layer");
             let at_row = row(&h);
             click(&mut h, at_row, Modifiers::NONE);
-            assert_eq!(layers(&h), 2, "left empty, it is removed");
+            assert_eq!(layers(&h), 3, "left empty, it stays, as in After Effects");
             click(&mut h, at, Modifiers::NONE);
         } else {
             h.state_mut().session.execute("text.edit", json!({"layer": title})).unwrap();
@@ -1734,3 +1734,19 @@ fn same_caret_application_text_replacement_rejects_the_previous_context_fence()
     h.run_steps(1);
     assert_eq!(edited(&h).1, "Aがbcd");
 }
+
+/// #2077: the Character panel's Line Join buttons set the stroke's corner style (Miter for new text).
+#[test]
+fn character_panel_line_join_buttons_set_the_join() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Type", "width": 640, "height": 360, "duration": 2})).unwrap();
+    let lid = s.execute("layer.newText", json!({"text": "Join", "size": 80, "applyStroke": true, "strokeWidth": 8})).unwrap()["layer"].as_u64().unwrap();
+    let mut h = harness(EffectcraftApp::new(s));
+    h.state_mut().show_panel(PanelKind::Character);
+    h.run_steps(3);
+    let join = |h: &Harness<'_, EffectcraftApp>| layer_doc(&h.state().session, LayerId(lid)).unwrap().line_join;
+    assert_eq!(join(&h), effectcraft_engine::keyframe::LineJoin::Miter);
+    let bevel = rect(&h, "character.lineJoin.bevel").center();
+    click(&mut h, bevel, Modifiers::NONE);
+    assert_eq!(join(&h), effectcraft_engine::keyframe::LineJoin::Bevel);
+}
diff --git a/crates/ui-egui/tests/it/ui_timeline_shapes.rs b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
index c8b45e8da..aadb52ffe 100644
--- a/crates/ui-egui/tests/it/ui_timeline_shapes.rs
+++ b/crates/ui-egui/tests/it/ui_timeline_shapes.rs
@@ -380,3 +380,55 @@ fn ctrl_v_pastes_svg_markup_as_a_shape_layer() {
     assert_eq!(c.layers.len(), 4);
     assert_eq!(c.layers[0].name, "Oval 2");
 }
+
+fn drag(h: &mut Harness<'_, EffectcraftApp>, from: Pos2, to: Pos2, cancel: bool) {
+    h.input_mut().events.push(Event::PointerMoved(from));
+    h.step();
+    h.input_mut().events.push(Event::PointerButton { pos: from, button: PointerButton::Primary, pressed: true, modifiers: Modifiers::NONE });
+    h.step();
+    for k in 1..=8 {
+        h.input_mut().events.push(Event::PointerMoved(from + (to - from) * (k as f32 / 8.0)));
+        h.step();
+    }
+    if cancel {
+        h.input_mut().events.push(Event::Key { key: Key::Escape, physical_key: None, pressed: true, repeat: false, modifiers: Modifiers::NONE });
+        h.step();
+    }
+    h.input_mut().events.push(Event::PointerButton { pos: to, button: PointerButton::Primary, pressed: false, modifiers: Modifiers::NONE });
+    h.run_steps(3);
+}
+
+/// #2210: an effect's row drags to a new place in the layer's effect stack, as in After Effects
+/// (not a marquee); Escape cancels the drag.
+#[test]
+fn effects_drag_to_a_new_place_in_the_timeline() {
+    let mut s = session();
+    let l = s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    for fx in ["Gaussian Blur", "Invert", "Tint"] {
+        s.execute("effect.apply", json!({"layers": [l], "effect": fx})).unwrap();
+    }
+    let effects = s.active_comp().unwrap().layer(LayerId(l)).unwrap().props.sub("effects").unwrap().clone();
+    let uids: Vec<u64> = effects.groups().map(|g| g.uid).collect();
+    let mut h = harness(s);
+    h.state_mut().ui.timeline.open_groups.insert(effects.uid);
+    open_layer(&mut h, l);
+    let names = |h: &Harness<'_, EffectcraftApp>| -> Vec<String> {
+        h.state().session.active_comp().unwrap().layer(LayerId(l)).unwrap().props.sub("effects").unwrap().groups().map(|g| g.name.clone()).collect()
+    };
+    let row = |h: &Harness<'_, EffectcraftApp>, uid: u64| {
+        let e = h.state().auto.find(&format!("timeline.group.{uid}.name")).unwrap_or_else(|| panic!("no row for {uid}"));
+        egui::Rect::from_min_size(pos2(e.rect[0], e.rect[1]), egui::vec2(e.rect[2], e.rect[3]))
+    };
+    // Tint above Gaussian Blur.
+    let (tint, blur) = (row(&h, uids[2]), row(&h, uids[0]));
+    drag(&mut h, tint.center(), pos2(blur.center().x, blur.min.y + 2.0), true);
+    assert_eq!(names(&h), ["Gaussian Blur", "Invert", "Tint"], "Escape cancels");
+    drag(&mut h, tint.center(), pos2(blur.center().x, blur.min.y + 2.0), false);
+    assert_eq!(names(&h), ["Tint", "Gaussian Blur", "Invert"]);
+    // Gaussian Blur (now second) below Invert, the last.
+    let (blur, invert) = (row(&h, uids[0]), row(&h, uids[1]));
+    drag(&mut h, blur.center(), pos2(invert.center().x, invert.max.y - 2.0), false);
+    assert_eq!(names(&h), ["Tint", "Invert", "Gaussian Blur"]);
+    h.state_mut().session.execute("edit.undo", json!({})).unwrap();
+    assert_eq!(names(&h), ["Tint", "Gaussian Blur", "Invert"], "one undo step per drop");
+}
diff --git a/crates/ui-egui/tests/it/ui_viewer.rs b/crates/ui-egui/tests/it/ui_viewer.rs
index 1fb36d90f..41cf5fe43 100644
--- a/crates/ui-egui/tests/it/ui_viewer.rs
+++ b/crates/ui-egui/tests/it/ui_viewer.rs
@@ -482,8 +482,9 @@ fn fill_rgb(h: &Harness<'_, EffectcraftApp>) -> [u8; 3] {
 fn shape_drag_ghost_shows_the_tools_own_shape_while_dragging() {
     let (from, to) = ([140.0, 100.0], [400.0, 300.0]);
     let centre = [270.0, 200.0];
-    // 6 comp px inside the box's top-left corner: inside a rectangle, outside every other kind.
-    let corner = [146.0, 106.0];
+    // 4 comp px inside the box's top-left corner: inside a rectangle, outside every other kind
+    // (a rounded corner of 20 px arcs past this point).
+    let corner = [144.0, 104.0];
     for (tool, fills_corner) in [(Tool::Rectangle, true), (Tool::RoundedRect, false), (Tool::Ellipse, false), (Tool::Polygon, false), (Tool::Star, false)] {
         let mut h = harness();
         h.state_mut().ui.tool = tool;
@@ -830,6 +831,48 @@ fn shift_drag_keeps_a_mask_vertex_to_one_axis() {
     assert!(free[0] > shifted[0] && free[1] > shifted[1], "without Shift both axes move: {shifted:?} -> {free:?}");
 }
 
+/// #999: a mask vertex dragged against the edge of the Composition panel pans the view, and the
+/// vertex keeps moving while the pointer is held there, as in After Effects.
+#[test]
+fn a_vertex_held_at_the_viewer_edge_pans_the_view() {
+    let mut h = harness();
+    let plate = layer_id(&h, "Plate");
+    let corners = [[100.0, 60.0], [500.0, 60.0], [500.0, 300.0], [100.0, 300.0]];
+    let mask = {
+        let s = &mut h.state_mut().session;
+        s.execute("layer.select", json!({"layers": [plate]})).unwrap();
+        let m = s.execute("mask.new", json!({"layer": plate, "vertices": corners, "closed": true})).unwrap()["mask"].as_u64().unwrap();
+        s.execute("mask.selectVertices", json!({"vertices": [{"layer": plate, "mask": m, "index": 0}]})).unwrap();
+        m
+    };
+    h.run_steps(2);
+    let pan0 = h.state().ui.viewer.pan;
+    let from = rect(&h, &format!("viewer.mask.{mask}.vertex.0")).center();
+    let edge = pos2(2.0, from.y);
+    h.input_mut().events.push(Event::PointerMoved(from));
+    h.input_mut().events.push(Event::PointerButton { pos: from, button: egui::PointerButton::Primary, pressed: true, modifiers: Default::default() });
+    h.step();
+    for i in 1..=6 {
+        h.input_mut().events.push(Event::PointerMoved(from + (edge - from) * (i as f32 / 6.0)));
+        h.step();
+    }
+    let reached = mask_path(&h, "Plate").vertices[0];
+    for _ in 0..20 {
+        h.step();
+    }
+    h.input_mut().events.push(Event::PointerButton { pos: edge, button: egui::PointerButton::Primary, pressed: false, modifiers: Default::default() });
+    h.run_steps(2);
+    let pan = h.state().ui.viewer.pan;
+    assert!(pan[0] > pan0[0] && pan[1] == pan0[1], "the view panned right to show more on the left: {pan0:?} -> {pan:?}");
+    let after = mask_path(&h, "Plate").vertices[0];
+    assert!(after[0] < reached[0], "the vertex kept moving left with the view: {reached:?} -> {after:?}");
+    // Back inside the view, nothing pans.
+    let still = h.state().ui.viewer.pan;
+    let mid = rect(&h, "viewer.comp").center();
+    drag(&mut h, mid, mid + vec2(5.0, 0.0));
+    assert_eq!(h.state().ui.viewer.pan, still);
+}
+
 /// #1769: a hidden masked layer keeps its mask path and vertices, and they remain editable.
 #[test]
 fn hidden_masked_layer_keeps_its_mask_path_editable() {
diff --git a/crates/ui-egui/tests/it/ui_viewer_trackpad.rs b/crates/ui-egui/tests/it/ui_viewer_trackpad.rs
new file mode 100644
index 000000000..55466371a
--- /dev/null
+++ b/crates/ui-egui/tests/it/ui_viewer_trackpad.rs
@@ -0,0 +1,156 @@
+//! Trackpad gestures in the Composition viewer: a two-finger scroll pans, a pinch (and the mouse
+//! wheel, also one that scrolls in pixels) zooms around the pointer (egui_kittest, UI logic only).
+
+use effectcraft_engine::Session;
+use effectcraft_ui_egui::EffectcraftApp;
+use effectcraft_ui_egui::dock::PanelKind;
+use egui::{Event, Rect, pos2, vec2};
+use egui_kittest::Harness;
+use serde_json::json;
+
+fn harness() -> Harness<'static, EffectcraftApp> {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "View", "width": 640, "height": 360, "duration": 4})).unwrap();
+    let mut h = Harness::builder().with_size(vec2(1600.0, 1000.0)).build_eframe(|_| EffectcraftApp::new(s));
+    h.state_mut().show_panel(PanelKind::Composition);
+    h.run_steps(4);
+    h
+}
+
+fn rect(h: &Harness<'_, EffectcraftApp>, id: &str) -> Rect {
+    let e = h.state().auto.find(id).unwrap_or_else(|| panic!("no {id}"));
+    Rect::from_min_size(pos2(e.rect[0], e.rect[1]), vec2(e.rect[2], e.rect[3]))
+}
+
+fn wheel(h: &mut Harness<'_, EffectcraftApp>, unit: egui::MouseWheelUnit, delta: egui::Vec2, modifiers: egui::Modifiers) {
+    h.input_mut().events.push(Event::MouseWheel { unit, delta, modifiers, phase: egui::TouchPhase::Move, source: egui::MouseWheelSource::Unknown });
+    h.run_steps(30);
+}
+
+#[test]
+fn trackpad_scroll_pans_the_composition() {
+    let mut h = harness();
+    let comp = rect(&h, "viewer.comp");
+    h.input_mut().events.push(Event::PointerMoved(comp.center()));
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(80.0, -40.0), Default::default());
+    let after = rect(&h, "viewer.comp");
+    let moved = after.min - comp.min;
+    assert!((moved.x - 80.0).abs() < 1.5 && (moved.y + 40.0).abs() < 1.5, "the scroll pans: {moved:?}");
+    assert!((after.width() - comp.width()).abs() < 0.5, "a scroll doesn't zoom: {} → {}", comp.width(), after.width());
+}
+
+#[test]
+fn pinch_and_mouse_wheel_zoom_around_the_pointer() {
+    let mut h = harness();
+    let comp = rect(&h, "viewer.comp");
+    let at = comp.min + comp.size() * 0.25;
+    h.input_mut().events.push(Event::PointerMoved(at));
+    h.input_mut().events.push(Event::Zoom(1.5));
+    h.run_steps(3);
+    let zoomed = rect(&h, "viewer.comp");
+    assert!((zoomed.width() / comp.width() - 1.5).abs() < 0.01, "the pinch zooms: {} → {}", comp.width(), zoomed.width());
+    let still = zoomed.min + zoomed.size() * 0.25;
+    assert!(still.distance(at) < 2.0, "the point under the pointer stays put: {at:?} vs {still:?}");
+    // A mouse wheel (it scrolls in lines) zooms too, and so does Alt + a trackpad scroll.
+    wheel(&mut h, egui::MouseWheelUnit::Line, vec2(0.0, 3.0), Default::default());
+    let wheeled = rect(&h, "viewer.comp");
+    assert!(wheeled.width() > zoomed.width() * 1.1, "the wheel zooms in: {} → {}", zoomed.width(), wheeled.width());
+    h.input_mut().events.push(Event::ModifiersChanged(egui::Modifiers::ALT));
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, -120.0), egui::Modifiers::ALT);
+    let out = rect(&h, "viewer.comp");
+    assert!(out.width() < wheeled.width() * 0.9, "Alt + scroll zooms out: {} → {}", wheeled.width(), out.width());
+}
+
+/// Browsers and some high-resolution wheels report a mouse wheel in pixels, as a trackpad does:
+/// it still zooms.
+#[test]
+fn a_pixel_unit_mouse_wheel_zooms() {
+    let mut h = harness();
+    let comp = rect(&h, "viewer.comp");
+    let at = comp.min + comp.size() * 0.25;
+    h.input_mut().events.push(Event::PointerMoved(at));
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, 120.0), Default::default());
+    let zoomed = rect(&h, "viewer.comp");
+    assert!(zoomed.width() > comp.width() * 1.1, "a pixel wheel zooms in: {} → {}", comp.width(), zoomed.width());
+    let still = zoomed.min + zoomed.size() * 0.25;
+    assert!(still.distance(at) < 2.0, "the point under the pointer stays put: {at:?} vs {still:?}");
+    // Shift turns the wheel's scroll sideways: still a wheel, and the next notch zooms.
+    h.input_mut().events.push(Event::ModifiersChanged(egui::Modifiers::SHIFT));
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, 120.0), egui::Modifiers::SHIFT);
+    h.input_mut().events.push(Event::ModifiersChanged(egui::Modifiers::NONE));
+    let before = rect(&h, "viewer.comp");
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, -120.0), Default::default());
+    let out = rect(&h, "viewer.comp");
+    assert!(out.width() < before.width() * 0.9, "the wheel still zooms: {} → {}", before.width(), out.width());
+}
+
+/// A straight vertical trackpad scroll pans when the touch phase says it is a trackpad,
+/// and after any diagonal scroll; a mouse wheel in lines takes the zoom back.
+#[test]
+fn a_vertical_trackpad_scroll_pans_once_the_trackpad_is_known() {
+    let mut h = harness();
+    let comp = rect(&h, "viewer.comp");
+    h.input_mut().events.push(Event::PointerMoved(comp.center()));
+    h.input_mut().events.push(Event::MouseWheel {
+        unit: egui::MouseWheelUnit::Point,
+        delta: egui::Vec2::ZERO,
+        modifiers: Default::default(),
+        source: egui::MouseWheelSource::Unknown,
+        phase: egui::TouchPhase::Start,
+    });
+    h.input_mut().events.push(Event::MouseWheel {
+        unit: egui::MouseWheelUnit::Point,
+        delta: vec2(0.0, 50.0),
+        modifiers: Default::default(),
+        source: egui::MouseWheelSource::Unknown,
+        phase: egui::TouchPhase::Move,
+    });
+    h.step();
+    h.input_mut().events.push(Event::MouseWheel {
+        unit: egui::MouseWheelUnit::Point,
+        delta: egui::Vec2::ZERO,
+        modifiers: Default::default(),
+        source: egui::MouseWheelSource::Unknown,
+        phase: egui::TouchPhase::End,
+    });
+    h.run_steps(30);
+    let panned = rect(&h, "viewer.comp");
+    assert!((panned.min.y - comp.min.y - 50.0).abs() < 1.5, "the scroll pans: {:?}", panned.min - comp.min);
+    assert!((panned.width() - comp.width()).abs() < 0.5, "a trackpad scroll doesn't zoom");
+    // Without phases (Windows, Linux, the web) it stays a trackpad.
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, 30.0), Default::default());
+    let again = rect(&h, "viewer.comp");
+    assert!((again.min.y - panned.min.y - 30.0).abs() < 1.5 && (again.width() - comp.width()).abs() < 0.5, "{again:?}");
+    // A wheel that scrolls in lines is a mouse: it zooms, and so does a pixel wheel after it.
+    wheel(&mut h, egui::MouseWheelUnit::Line, vec2(0.0, 3.0), Default::default());
+    let zoomed = rect(&h, "viewer.comp");
+    assert!(zoomed.width() > again.width() * 1.1, "the wheel zooms: {} → {}", again.width(), zoomed.width());
+    wheel(&mut h, egui::MouseWheelUnit::Point, vec2(0.0, 120.0), Default::default());
+    assert!(rect(&h, "viewer.comp").width() > zoomed.width() * 1.1, "a pixel wheel zooms again");
+}
+
+/// Where the platform names the device (macOS), a straight vertical trackpad scroll pans at once
+/// and a wheel in points zooms.
+#[test]
+fn the_wheel_source_decides_where_the_platform_reports_it() {
+    let mut h = harness();
+    let comp = rect(&h, "viewer.comp");
+    let at = comp.min + comp.size() * 0.25;
+    h.input_mut().events.push(Event::PointerMoved(at));
+    let scroll = |h: &mut Harness<'_, EffectcraftApp>, source, dy| {
+        h.input_mut().events.push(Event::MouseWheel {
+            unit: egui::MouseWheelUnit::Point,
+            delta: vec2(0.0, dy),
+            modifiers: Default::default(),
+            phase: egui::TouchPhase::Move,
+            source,
+        });
+        h.run_steps(30);
+    };
+    scroll(&mut h, egui::MouseWheelSource::Trackpad, 40.0);
+    let panned = rect(&h, "viewer.comp");
+    assert!((panned.min.y - comp.min.y - 40.0).abs() < 1.5, "the trackpad pans: {:?}", panned.min - comp.min);
+    assert!((panned.width() - comp.width()).abs() < 0.5, "a trackpad scroll doesn't zoom");
+    scroll(&mut h, egui::MouseWheelSource::Wheel, 120.0);
+    assert!(rect(&h, "viewer.comp").width() > panned.width() * 1.1, "the wheel zooms");
+}
diff --git a/docs/agents.md b/docs/agents.md
index d84442a84..172e5c4c6 100644
--- a/docs/agents.md
+++ b/docs/agents.md
@@ -272,10 +272,10 @@ build real projects through these interfaces; they are worked examples of everyt
   then `keys.velocity {"outSpeed":0,"outInfluence":33.33}`.
 * **Gradients**: `set_property {"path":"contents/gfill/colors","value":["#0080ff","#ffff00"]}` or
   `{"colors":[[0,"#0080ff"],[1,[1,1,0]]],"opacities":[[0,1],[1,0.5]]}`.
-* **Image sequences**: `file.import {"paths":["/r/shot_0001.png"]}` imports the file's whole
-  numbered run as one item (several picked frames: that range; a folder: each run in it;
-  `"sequence": false`: one still; dropped files, `"drag": true`, import as stills unless
-  `"sequence": true`, as in After Effects; `"alphabetical": true`: Force Alphabetical Order, the files
+* **Image sequences**: `file.import {"paths":["/r/shot_0001.png"], "sequence": true}` imports the
+  file's whole numbered run as one item (several picked frames: that range; a folder: each run in
+  it, also without `sequence`). Without `"sequence": true` a picked or dropped numbered file imports
+  as one still, as in After Effects; `"alphabetical": true`: Force Alphabetical Order, the files
   play one after another) at `frameRate` or 30 fps (Settings ▸ Import). Missing frames show
   colour bars, as in After Effects. `file.interpretFootage {"items":[id], "frameRate":12,
   "startTimecode":1001}` conforms them and sets Override Start (the item and layers that ran to its end get the new
@@ -540,7 +540,7 @@ indices): character attributes
 3. `layer.setText {"range":[6,11], "size":40, "fill":"#ff5500"}` styles the selection (the
    Character panel does the same); with an empty range it sets the style the next typed text takes.
 4. `edit.copy`, `edit.paste`, `edit.pasteTextMatchFormatting` and `edit.pasteTextFormattingOnly`
-   work on the selected text; `text.endEdit` commits (an empty Type-tool layer is removed).
+   work on the selected text; `text.endEdit` commits (an empty Type-tool layer is kept, as After Effects does).
 
 Fonts: `text.fonts` (MCP `list_fonts`) lists every family a text layer can use, bundled and installed, with its
 styles, origin (`bundled`, `system`, `user`), `variable` (it has variation axes) and own-language name
@@ -622,6 +622,13 @@ Extension points and the bundled extensions: [plugins.md](plugins.md).
   Dragged onto another property's name or value, in the Timeline or Effect Controls
   (`effectControls.prop.<uid>.value[.<d>]`), it runs `prop.pickWhip`: the reference replaces the
   property's expression, or is added as one, and the expression is enabled.
+* Parent and Track Matte for several layers: on a selected layer's row, the Timeline's Parent
+  menu and pick whip (`timeline.layer.<id>.parent`, `timeline.layer.<id>.pickWhip`) and its Track
+  Matte menu and pick whip (`timeline.layer.<id>.trackMatte`,
+  `timeline.layer.<id>.trackMattePickWhip`) set every selected layer's (on an unselected row,
+  that layer's), in one undo step. Directly: `layer.setParent {layers, parent}` and
+  `layer.setTrackMatte {layers, matte, kind}`, where `kind: "preserve"` keeps each layer's
+  own matte mode.
 * A property's menu (right-click its name; entries `timeline.prop.<uid>.menu.<entry>`): Reset
   (`prop.reset`: no expression, and the property's default value, an effect parameter's or a
   Transform property's; an animated property keeps its keyframes and gets the default as a
diff --git a/docs/architecture.md b/docs/architecture.md
index 4ffdd9dd7..4fad74486 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -401,7 +401,10 @@ hierarchical block-matching optical flow and a bidirectional warp (Pixel Motion,
 its nested layers straight into the parent with concatenated transforms (one resample), so
 nested blend modes and adjustment layers act on the parent's layers; nested 3D layers use the
 parent's camera and lights and, when the precomp layer is 3D, are depth-sorted with the parent's
-3D run. Masks, effects or styles force a flattened render. Text layers are always rasterised at
+3D run. Essential Properties overrides (properties, Font and Media Replacement) travel with the
+collapsed context and are applied while the nested layers are evaluated, so they do not force a
+flattened render or clip at the precomp's frame. Masks, effects or styles force a flattened
+render. Text layers are always rasterised at
 their on-screen scale, as text is vector in After Effects; on shape layers and vector footage the
 switch is Continuously Rasterize and does the same. Quality: Draft samples
 nearest-neighbour, Wireframe draws the layer bounds. Slip edit (`layer.slip`, Alt+PageUp/Down,
@@ -468,8 +471,10 @@ effects crate, hence the `effects → track` edge.
 `essential` field lists its exposed controls (properties, Media Replacement, groups, comments).
 Every precomp layer of such a comp gets an Essential Properties group (`GroupKind::Essential`,
 children `eg<control id>`), kept in step by `Session::edit`; editing a child overrides it for
-that instance. The renderer draws an instance with overrides from a copy of the project with the
-overridden source properties set (`essential::with_overrides`). Templates are `.ectemplate`
+that instance. A collapsed instance carries its property, Font and Media Replacement overrides
+into the nested render context (`Collapsed`, `EvalCtx::{property_overrides, media_overrides}`);
+other instances are drawn from a copy of the project with the overridden source properties set
+(`essential::with_overrides`). Templates are `.ectemplate`
 ZIPs: `manifest.json` (controls), `project.ecproj` (the comp and its dependencies), `media/…` and
 `poster.png`; importing offsets every id past the project's (`essential::offset_ids`).
 **Responsive Design — Time**: a time-stretched precomp maps time piecewise so its protected
diff --git a/docs/control-protocol.md b/docs/control-protocol.md
index c68711ea5..d9049306c 100644
--- a/docs/control-protocol.md
+++ b/docs/control-protocol.md
@@ -103,7 +103,7 @@ Points are logical window coordinates. A target is `{id}` (the element's centre;
 | `ui.click` | `{id \| x,y, button?: left\|right\|middle, count?, modifiers?}` |
 | `ui.move` | `{id \| x,y}` |
 | `ui.drag` | `{from: target, to: target, steps? (12), modifiers?}`: press, move, release |
-| `ui.scroll` | `{id \| x,y, dx, dy}` |
+| `ui.scroll` | `{id \| x,y, dx?, dy?, unit?: point\|line, source?: wheel\|trackpad, pinch?, modifiers?}`: `line` is a mouse wheel (zooms the viewers); `point` (default) is a pixel-precise scroll; `source: trackpad` pans the viewers (as on macOS); with no `source` the viewers take a scroll in points as a wheel until one moves on both axes (a trackpad: from then on it pans); `pinch` is a trackpad pinch's zoom factor |
 | `ui.key` | `{key}`, for example `Space`, `F9`, `Cmd+Z`, `Cmd+Shift+Z`, `PageDown`, `Escape` |
 | `ui.type` | `{text}`: text input into the focused field |
 
diff --git a/docs/effects.md b/docs/effects.md
index b8214e438..c6fb40922 100644
--- a/docs/effects.md
+++ b/docs/effects.md
@@ -3,11 +3,11 @@
 <!-- Generated from the effect registry (crates/effects/src/catalog.rs); do not edit by hand.
      Regenerate: UPDATE_DOCS=1 cargo test -p effectcraft-effects --lib effects_doc_is_current -->
 
-EffectCraft ships 307 effects with 3032 parameters in total, grouped into the same categories as the Effects & Presets panel. Every effect is our own implementation, written from public behaviour descriptions and standard image-processing literature. Parameter names, order, popup options, units, defaults and ranges follow the reference application so that projects, expressions and muscle memory carry over.
+EffectCraft ships 308 effects with 3033 parameters in total, grouped into the same categories as the Effects & Presets panel. Every effect is our own implementation, written from public behaviour descriptions and standard image-processing literature. Parameter names, order, popup options, units, defaults and ranges follow the reference application so that projects, expressions and muscle memory carry over.
 
 - **GPU**: 280 effects also run on the GPU compositor with identical results.
-- **32**: 307 effects process 32-bit float (HDR, overbright) pixels without clamping.
-- **Status**: 307 implemented in full, 0 partial (what is missing is listed).
+- **32**: 308 effects process 32-bit float (HDR, overbright) pixels without clamping.
+- **Status**: 308 implemented in full, 0 partial (what is missing is listed).
 
 Effects are addressed by id (`ec.<category>.<name>`) or display name in commands, scripts and the control channel, and every parameter by its id (`effects/#1/blurriness`).
 
@@ -16,6 +16,7 @@ Effects are addressed by id (`ec.<category>.<name>`) or display name in commands
 | Effect | Id | Params | GPU | 32 | Status |
 |---|---|---:|:-:|:-:|---|
 | 3D Channel Extract | `ec.3d.channelextract` | 6 | GPU | 32 | Implemented |
+| 3D Layer Instance | `ec.3d.instance3d` | 1 |  | 32 | Implemented |
 | Cryptomatte | `ec.3d.cryptomatte` | 4 | GPU | 32 | Implemented |
 | Depth Matte | `ec.3d.depthmatte` | 3 | GPU | 32 | Implemented |
 | Depth of Field | `ec.3d.depthoffield` | 4 | GPU | 32 | Implemented |
diff --git a/docs/fidelity/README.md b/docs/fidelity/README.md
index fc780016b..0398118c5 100644
--- a/docs/fidelity/README.md
+++ b/docs/fidelity/README.md
@@ -71,6 +71,45 @@ After the fix, all ten tangents equal AE's to the printed 0.001 px, and the two
 test `spatial_auto_bezier_tangents_follow_after_effects` checks the rule on other original keys,
 including a timing change. AE's output stays local; only the script and these scores are tracked.
 
+## Justify All with the every-line composer
+
+Measured on 19 October 2026 with After Effects 2026 (26.2) on box text (EXPORTER read-back t6):
+with Justify All, AE stretches the paragraph's last line too and breaks the lines so that it is not
+a lone word (4 / 4 / 4 words where the other justifications break 6 / 6 / 1). EffectCraft's
+every-line composer ignored the last line's slack and left "twelve" alone on a stretched line; it now
+counts that slack for Justify All, and every word starts within 1 px of AE's. Regression test:
+`justify_all_balances_the_lines_with_the_every_line_composer`.
+
+## Right-to-left point text with a justified paragraph
+
+Measured on 19 October 2026 with After Effects 2026 (26.2) (EXPORTER read-back t7): right-to-left
+point text whose paragraph has a justified code (justify last left / centre / right, justify all)
+sits flush right at its anchor, like right-aligned text. EffectCraft placed it by the last-line
+side (left / centre / left). Now flush right; left-to-right point text is unchanged (not measured).
+Regression test: `rtl_point_text_with_a_justified_paragraph_is_flush_at_its_start`. Still open:
+AE wraps right-to-left box text slightly wider (its word gaps are 1–2 px narrower than in
+left-to-right text with the same font), so a 300 px box fits a word more per line.
+
+## Text animator tracking
+
+Measured on 19 October 2026 with After Effects 2026 (26.2): a text animator's Tracking Amount is in
+pixels, not 1/1000 em like the Character panel's tracking (Amount 30 adds 30 px between neighbouring
+characters at 80 px and at 40 px, half before and half after each), and a Subtract range selector
+over characters the first selector leaves out keeps them at 0 instead of tracking them negatively.
+With both, the EXPORTER's t8 layer D (Tracking 30 on characters 2–4 by index, a Subtract selector
+over the last 20 %) puts every glyph where AE does (it ended 88 px short). The "Tracking In" text
+preset now animates 40 → 0 px (was 400 → 0 thousandths of an em). Lottie export is unchanged (not
+checked against a player). Regression tests: `animator_tracking_is_in_pixels_as_in_after_effects`,
+`modes_combine`.
+
+## Per-character 3D rotation order
+
+Measured on 19 October 2026 with After Effects 2026 (26.2) (case 931: "H" at 400 px, per-character
+3D, animator X / Y / Z Rotation 40 / 30 / 20): a character turns as a 3D layer does, Rx · Ry · Rz
+(Z first). EffectCraft composed Rz · Ry · Rx, so the glyph faced another way (23 of 5184 grid points
+off, max 255); now 3 at the anti-aliased edge (mean 0.015). Regression test:
+`per_character_rotation_turns_z_first_as_a_3d_layer`.
+
 ## Rectangle path start point
 
 Measured on 19 October 2026 with After Effects 2026 (26.2) on 400 × 300 shape rectangles with Trim
diff --git a/docs/footage.md b/docs/footage.md
index bd99cbeb2..f23bcdcc7 100644
--- a/docs/footage.md
+++ b/docs/footage.md
@@ -129,9 +129,10 @@ including files overwritten at the same path and byte size.
   and 3D models are not sources, and a composition can't be nested in itself. Alt-dragging onto a
   layer is one layer at a time, as in After Effects.
   Agents: `layer.replaceSource {"item": id, "layers": [ids]}`.
-- **File ▸ Replace Footage ▸ File…** (Ctrl+H) points the item at another file. Pick a numbered
-  file to replace it with that file's whole sequence (`file.replaceFootage {"path": …,
-  "sequence": false}` for one frame).
+- **File ▸ Replace Footage ▸ File…** (Ctrl+H) points the item at another file. A still stays a
+  still, and a sequence item keeps bringing the new numbered file's run; pass
+  `sequence: true` to bring a numbered still's whole run (`file.replaceFootage {"path": …,
+  "sequence": true}`), or `sequence: false` for one frame.
 - **Replace with Precomposition (used N times)**, right-clicking a footage item or solid in the
   Project panel, puts the item in a new composition of its size,
   pixel aspect and frame rate, in the same folder, and switches every layer in every composition
diff --git a/docs/gaps.md b/docs/gaps.md
index 353969453..d67f35e59 100644
--- a/docs/gaps.md
+++ b/docs/gaps.md
@@ -67,7 +67,7 @@ are grouped by area; the issue tracker has the rest.
 | 8 | **Mask and shape bugs** | Open: #1004 mask vertex multi-select, #999 auto-pan, #1042 / #1033 vertex nodes under the bounding box, #959 / #960 shape group toggles and operators. Now closed: #510, #513, #527, #509, #303, #553, #932 (Convert To Bezier Path on a shape layer's parametric path) | Masks are core compositing | 10–20 h | G2 · [target-app-parity.md](target-app-parity.md) |
 | 9 | **Effect behaviour bugs** | #580, #463 Curl Noise, #369 Motion Tile output size, #943 Turbulent Displace Evolution, #473 Cryptomatte selection (quoted names with commas fixed, 3b7f1ace; UI and GPU time open), #474 multi-layer EXR (decode shared, faffad3a; f16 storage and cache sizing open). Closed: #526, #514, #533–#536 | Each one breaks a look someone built | 10–20 h | G1/G2 · [effects-parity.md](effects-parity.md) |
 | 10 | **Colour pipeline differences** | #340 ProRes 4444 tagged bt709 but sRGB-encoded (open); ACES 2.0 / OCIO 2.5 configs (26.5) missing; now closed: #494 32-bpc blend modes, #495 and #750 Working Gamma 2.4, #546 / #547 viewer colour | Wrong colour in delivery is a client-visible failure | 15–30 h | G1 · [file-format-parity.md](file-format-parity.md) |
-| 11 | **Text rendering and layout** | Open: #453 CJK text in comps, #316 paragraph alignment inverted (maintainers' tests show Left/Right correct; asked for a project), #417 soft at Fit (mostly fixed by #444), #550 toolbar font options. Closed: #483, #583 | Text is in almost every motion graphic | 10–20 h | G2 · [ui-parity.md](ui-parity.md) |
+| 11 | **Text rendering and layout** | #453 CJK text in comps: the Han fallback now reaches the installed Chinese faces; open: #316 paragraph alignment inverted (maintainers' tests show Left/Right correct; asked for a project), #417 soft at Fit (mostly fixed by #444), #550 toolbar font options. Closed: #483, #583 | Text is in almost every motion graphic | 10–20 h | G2 · [ui-parity.md](ui-parity.md) |
 | 12 | **3D interaction and depth** | No 3D transform gizmos (#392, #347); camera aperture (#260); reflections (#261); extruded surface materials beyond Front / Bevel / Side / Back Color (fb5a5e9a; #315 closed); #307 reopened (the viewer's renderer button now shows and switches the renderer, #645); Z position (#489) closed | Advanced 3D is After Effects' growth area since 2023 | 20–35 h | G2 · [ui-parity.md](ui-parity.md) |
 | 13 | **3D model formats and materials** | After Effects 26 imports FBX, USD/USDZ, STL besides glTF and OBJ (`usd_plugins`), and Substance 3D materials with mesh displacement (26.0–26.2); we read glTF, OBJ, STL (binary and ASCII, with facet colours) and FBX 7.x (binary and ASCII: meshes, hierarchy, Lambert/Phong materials and textures; no FBX animation or skinning yet) | Product shots and 3D scenes come as FBX/USDZ | 25–45 h | — · [file-format-parity.md](file-format-parity.md) |
 | 14 | **Object Matte** (26.2, disk cache in 26.5) | First slice (#783): the Object Matte effect (Effect ▸ Matte) and `objectMatte.apply` turn a point (and optional box) on a reference frame into a matte and follow the object up to 600 frames each way, or segment every frame on its own; Roto Brush's engine, cache and model (MobileSAM from Settings ▸ Roto Brush, classical graph cut without it). Since then: the Object Matte tool in the viewer (click / drag a box, hover crosshair), the box as the model's box prompt, background tracking with progress and cancel, Freeze, and segmentations kept in the disk cache (26.5). Missing: a comparison with After Effects ([plan](fidelity/object-matte.md)) | The new one-click roto | 10–20 h | G7 · [target-app-parity.md](target-app-parity.md) |
@@ -169,6 +169,11 @@ The most important missing piece: it turns every other estimate here into a meas
   a Radial Stroke swatch on a selected shape layer and get the Gradient Editor on its Gradient Fill
   / Gradient Stroke Colors (OK saves); without such a gradient the swatch still opens the options,
   and the words, Solid swatches and Alt-click are unchanged.
+- Regression evidence for [#1306](https://github.com/storytold/effectcraft/issues/1306) (from
+  #1072): the `ui_expression_values` tests, checked headlessly on Windows, read the colour the
+  values are painted in. Expression-driven vectors, angles and scalars are red in the Timeline,
+  Effect Controls and Properties panel, in dark and light themes, hovered too; disabled, removed
+  and empty expressions show the ordinary colour.
 - Regression evidence for the reports of 6 October, checked headlessly on Windows: real pointer
   drags in `ui_drag_drop` (Project items into the Timeline between layers and at a time, and onto
   the viewer; an effect onto a layer in the viewer: #85, #88, #89), `ui_render_queue` (a template
diff --git a/docs/hardware-parity.md b/docs/hardware-parity.md
index 0a0a85a97..c25da4928 100644
--- a/docs/hardware-parity.md
+++ b/docs/hardware-parity.md
@@ -23,7 +23,7 @@ monitors are missing, and two GPU start-up failures are open.
 | HDR display | HDR monitoring on EDR / HDR displays | tone-mapped SDR view; no EDR output | no HDR output | no | no | Colour engine handles HDR maths (Rec. 2100 PQ/HLG output files) |
 | Pen tablets (pressure, tilt) | yes, for Paint and Roto | Brushes panel has pressure options, but no tablet pressure is read | same | same | same | Paint strokes store pressure per vertex; input never fills it |
 | Multiple monitors | panels and windows across screens | panels move into their own native windows on any screen (Move Panel to New Window; desktop builds) | same | same (#486) | — | gap 20 |
-| Touch / trackpad gestures | pinch zoom in viewers | egui pointer and scroll; no pinch-to-zoom audited | — | — | — | — |
+| Touch / trackpad gestures | pinch zoom in viewers | Composition and Layer viewers: two-finger scroll pans, pinch zooms around the pointer (Alt + scroll and the mouse wheel zoom too); Timeline pinch zooms time | two-finger scroll pans once it moves diagonally (a pixel-precise wheel keeps zooming); pinch arrives as Ctrl + scroll and zooms | same | same | No rotate or swipe gestures; tested in `ui_viewer_trackpad.rs` (UI logic, not on hardware) |
 | Audio hardware | Core Audio / ASIO / WASAPI, device choice, latency | cpal output; preview sound late after a start offset (#504 open; #554 closed) | cpal | cpal (ALSA) | Web Audio | No input or device latency settings |
 | Machine learning acceleration | Apple Neural Engine / GPU for Object Matte, Roto Brush 3 | CPU inference (pure Rust, rayon) | CPU | CPU | CPU | No GPU inference for MobileSAM or MediaPipe |
 | Memory management | RAM reserve, disk cache | RAM Reserved, Reduce Cache When Low on Memory, disk cache | same | same | OPFS disk cache | good |
diff --git a/docs/preferences.md b/docs/preferences.md
index ce96da0bf..2402b9a32 100644
--- a/docs/preferences.md
+++ b/docs/preferences.md
@@ -42,6 +42,7 @@ Commands (CLI, MCP, control channel):
 - `startup.windowGraphics`: Window Graphics (`auto` / `gl`), what the desktop window draws with from the next launch. `auto` lets the platform pick (DirectX 12, Vulkan or Metal); `gl` uses OpenGL, with CPU compositing, for graphics drivers that crash with the others. A launch leaves a `launch-pending` marker in the settings folder until its window has been drawing for a few seconds (or the app quits normally before that); a launch that stops earlier (a graphics driver crashing as the window opens or as its surface is re-created) leaves the marker behind, and the next launch switches to `gl` and says so (not on macOS, which has no OpenGL backend). `WGPU_BACKEND` overrides both.
 - `project.useTemplate`: New Project Loads Template
 - `project.templatePath`: Template Project
+- `project.compactProjectFiles`: Save Compact Project Files (default off). Off: File ▸ Save writes `.ecproj` files as indented JSON, one value per line, easy to read and diff in version control. On: compact JSON on one line, smaller and faster to save and open. Either opens the same; auto-saves, XML copies and template packages are not affected.
 - `autoSave.enabled`: Automatically Save Projects
 - `autoSave.intervalMinutes`: Save Every
 - `autoSave.maxVersions`: Maximum Project Versions
diff --git a/docs/testing.md b/docs/testing.md
index 67d622fd9..d556fdc4f 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -5,6 +5,10 @@ cargo test --workspace     # everything
 cargo xtask ci             # fmt, clippy -D warnings, tests, layers, assets, wasm
 ```
 
+The `dev` profile keeps debug info to line tables (fast builds, readable backtraces). To debug
+interactively — local variables, parameters, column breakpoints — build with the `dev-full`
+profile: `cargo run --profile dev-full -p effectcraft -- --demo` (see `CONTRIBUTING.md`).
+
 `cargo xtask ci` builds in the dev profile and runs the tests with `cargo nextest run` (plus
 `cargo test --doc`) when `cargo-nextest` is installed, and with `cargo test` otherwise. It then
 runs `missing_translations_report` with `--nocapture`, which prints the interface strings each
diff --git a/docs/web.md b/docs/web.md
index c18f7e869..1cdecab00 100644
--- a/docs/web.md
+++ b/docs/web.md
@@ -242,6 +242,25 @@ Window ▸ Media Browser browses a virtual tree (`src/browse.rs`):
 
 `mediaBrowser.list` reports the places and these actions; `mediaBrowser.action {action}` runs one.
 
+### Startup project
+
+By default the page opens the last visit's project, and the demo project on a first visit. A
+`startup` key in `effectcraft-config.json` (next to `index.html`) changes that:
+
+```json
+{"startup":"empty"}
+```
+
+| Value | On load |
+|---|---|
+| `"last"` (or no key) | the last visit's project; the demo project on a first visit |
+| `"empty"` | the last visit's project; a blank project on a first visit, never the demo |
+| `"demo"` | the demo project, whatever the last visit left; the session is not saved, so the last visit's project stays as it was |
+
+The `?empty` and `?demo` URL flags still win. A missing, invalid or non-JSON file, or an unknown
+value, is the default. The file is fetched once per page load; serve it with
+`Cache-Control: no-cache` (the service worker never caches it).
+
 ### Audio
 
 Audio preview goes through **Web Audio**: an AudioWorklet (`audio-worklet.js`; a
diff --git a/extensions/scriptui-panels/Ease Presets.jsx b/extensions/scriptui-panels/Ease Presets.jsx
index 6f6eadae5..9f4ea2185 100644
--- a/extensions/scriptui-panels/Ease Presets.jsx	
+++ b/extensions/scriptui-panels/Ease Presets.jsx	
@@ -18,6 +18,8 @@
 // segment on that side. So a selected pair gets the whole curve, and a single key works too.
 // Roving keys are skipped: they pass speed straight through (their sides stay linear), so an ease
 // set on them wouldn't play.
+// The built-in Linear preset uses Linear interpolation, including on unused endpoint sides
+// so a fully linear key has a diamond icon; the other presets use Bezier.
 //
 // User presets are kept with app.settings (section "Ease Presets", key "userPresets") as JSON:
 // {"version": 1, "presets": [{"name": …, "curve": {"outInfluence", "outSpeed", "inInfluence",
@@ -29,6 +31,7 @@
   var MAX_NAME = 64;
   var MIN_INFLUENCE = 0.1;
   var MAX_SPEED = 100;
+  var LINEAR = KeyframeInterpolationType.LINEAR;
   var BEZIER = KeyframeInterpolationType.BEZIER;
   var HOLD = KeyframeInterpolationType.HOLD;
 
@@ -178,16 +181,16 @@
 
   // Ease one side of key `k` with `eases`, leaving its other side as it plays (auto-Bezier and
   // linear sides keep their shape; a continuous key stops being continuous, its sides now differ).
-  function easeSide(p, k, out, eases) {
+  function easeSide(p, k, out, eases, interpolation) {
     var inType = p.keyInInterpolationType(k), outType = p.keyOutInterpolationType(k);
     var inEase = p.keyInTemporalEase(k), outEase = p.keyOutTemporalEase(k);
     if (p.keyTemporalContinuous(k)) p.setTemporalContinuousAtKey(k, false);
     if (out) {
       p.setTemporalEaseAtKey(k, inEase, eases);
-      p.setInterpolationTypeAtKey(k, inType, BEZIER);
+      p.setInterpolationTypeAtKey(k, inType, interpolation);
     } else {
       p.setTemporalEaseAtKey(k, eases, outEase);
-      p.setInterpolationTypeAtKey(k, BEZIER, outType);
+      p.setInterpolationTypeAtKey(k, interpolation, outType);
     }
   }
 
@@ -201,7 +204,7 @@
   // Ease the sides `mode` names ("In", "Out" or "In-Out") of every selected keyframe with `c`, in
   // one undo step: a side with a neighbouring key, scaled to the segment on that side. Returns
   // {eased, roving}: the number of keyframes eased, and of selected roving keyframes skipped.
-  function applyCurve(c, mode) {
+  function applyCurve(c, mode, interpolation) {
     var keyed = selectedKeyed(), sides = [], keys = 0, roving = 0;
     var doIn = mode !== "Out", doOut = mode !== "In";
     // Every side and its eases first: the segments are measured before any key changes.
@@ -214,16 +217,16 @@
           continue;
         }
         var s = doIn && k > 1 ? slopes(p, k - 1) : null;
-        if (s) sides.push({ prop: p, key: k, out: false, eases: eases(s, c.inSpeed, c.inInfluence) });
+        if (s || (doIn && interpolation === LINEAR)) sides.push({ prop: p, key: k, out: false, eases: s ? eases(s, c.inSpeed, c.inInfluence) : p.keyInTemporalEase(k) });
         s = doOut && k < p.numKeys ? slopes(p, k) : null;
-        if (s) sides.push({ prop: p, key: k, out: true, eases: eases(s, c.outSpeed, c.outInfluence) });
+        if (s || (doOut && interpolation === LINEAR)) sides.push({ prop: p, key: k, out: true, eases: s ? eases(s, c.outSpeed, c.outInfluence) : p.keyOutTemporalEase(k) });
         if (sides.length > before) keys++;
       }
     }
     if (!sides.length) return { eased: 0, roving: roving };
     app.beginUndoGroup("Apply Ease Preset");
     try {
-      for (var e = 0; e < sides.length; e++) easeSide(sides[e].prop, sides[e].key, sides[e].out, sides[e].eases);
+      for (var e = 0; e < sides.length; e++) easeSide(sides[e].prop, sides[e].key, sides[e].out, sides[e].eases, interpolation);
     } finally {
       app.endUndoGroup();
     }
@@ -384,7 +387,10 @@
 
   function apply(c, what) {
     var m = mode.selection ? mode.selection.text : "In-Out";
-    var r = applyCurve(c, m), n = r.eased;
+    // Linear is an interpolation type too, so its keys get diamond icons. Edited speeds
+    // make a custom Bezier curve even while Linear remains selected in the list.
+    var interpolation = list.selection && list.selection.text === "Linear" && c.outSpeed === 1 && c.inSpeed === 1 ? LINEAR : BEZIER;
+    var r = applyCurve(c, m, interpolation), n = r.eased;
     var side = m === "In" ? "before it" : m === "Out" ? "after it" : "next to it";
     var skipped = r.roving > 0 ? "skipped " + r.roving + " roving keyframe(s); turn off Roving to ease them" : "";
     if (n > 0) status.text = "Eased " + n + " keyframe(s) (" + m + ") with " + what + (skipped ? "; " + skipped : "");
diff --git a/packaging/web/README.md b/packaging/web/README.md
index 0a1f56fe8..672d9ad67 100644
--- a/packaging/web/README.md
+++ b/packaging/web/README.md
@@ -58,6 +58,19 @@ location /effectcraft/ {
 
 Local test: `python3 -m http.server 8765` inside the folder, then open http://localhost:8765/.
 
+## Startup project (optional)
+
+To choose what the page opens on load, add an `effectcraft-config.json` next to `index.html`:
+
+```json
+{"startup":"empty"}
+```
+
+`"empty"` restores the last visit's project and otherwise starts blank (never the demo); `"demo"`
+always opens the demo project without saving the session (the last visit's project stays); `"last"` (the default) restores the last visit's project and shows
+the demo on a first visit. Serve the file with `Cache-Control: no-cache`. Details:
+[docs/web.md](https://github.com/storytold/effectcraft/blob/main/docs/web.md#startup-project).
+
 ## Embedding in a page (iframe)
 
 ```html
diff --git a/packaging/web/_headers b/packaging/web/_headers
index 013e1cf8a..e59592fb1 100644
--- a/packaging/web/_headers
+++ b/packaging/web/_headers
@@ -12,3 +12,6 @@
 
 /index.html
   Cache-Control: no-cache
+
+/effectcraft-config.json
+  Cache-Control: no-cache
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index afc767de2..0f8072840 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -13,3 +13,4 @@ serde_json = { workspace = true }
 
 chrono = { workspace = true }
 tempfile = "3"
+pkg-config = "0.3"
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index da8026d78..ad03cada7 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -407,6 +407,62 @@ fn serve_dir(dir: &std::path::Path, port: u16) -> Result<(), String> {
     Ok(())
 }
 
+/// The guidance printed when the ALSA pkg-config package is missing. Split out so the tests can
+/// check the package names without needing a machine that is actually missing them.
+#[cfg(target_os = "linux")]
+fn audio_backend_missing_hint(pkg_config_stderr: Option<&str>) -> String {
+    let mut hint = String::from(
+        "Linux audio needs the ALSA development package, and pkg-config cannot find it.\n\
+         The desktop app plays preview sound through cpal, whose alsa-sys dependency asks\n\
+         pkg-config for `alsa`; without the package the build dies minutes later with an\n\
+         unrelated-looking linker error.\n\
+         \n\
+         Fedora:         sudo dnf install alsa-lib-devel\n\
+         Debian/Ubuntu:  sudo apt install libasound2-dev\n\
+         Arch:           sudo pacman -S alsa-lib\n\
+         \n\
+         Install one of those and run `cargo xtask ci` again. If you cannot install it, point\n\
+         PKG_CONFIG_PATH at a directory holding an `alsa.pc` whose Libs line names your system's\n\
+         libasound (usually `libasound.so.2`); every CI run will need that variable set.",
+    );
+    if let Some(stderr) = pkg_config_stderr {
+        hint.push_str("\n\npkg-config said: ");
+        hint.push_str(stderr);
+    }
+    hint
+}
+
+/// `cargo xtask ci` builds the desktop app on the host, so on Linux it needs a usable ALSA
+/// pkg-config package before the build dies minutes later at link time. The probe goes through
+/// the same `pkg-config` crate alsa-sys's build script uses, so the executable and search-path
+/// lookup match by construction: `PKG_CONFIG` and its target-scoped variants, then `pkg-config`
+/// on `PATH` with a `pkgconf` fallback, plus the scoped `PKG_CONFIG_PATH`/`LIBDIR`/`SYSROOT_DIR`.
+/// A probe that ran and said no is "ALSA missing"; one that could not run is reported separately,
+/// so a machine with only `pkgconf` does not fail a build that would succeed.
+#[cfg(target_os = "linux")]
+fn audio_backend() -> Result<(), String> {
+    // cargo_metadata off: xtask is not a build script, so the crate's rerun-if-env lines would
+    // only clutter the ci log.
+    match pkg_config::Config::new().cargo_metadata(false).probe("alsa") {
+        Ok(_) => Ok(()),
+        Err(pkg_config::Error::ProbeFailure { output, .. }) | Err(pkg_config::Error::Failure { output, .. }) => {
+            let stderr = String::from_utf8_lossy(&output.stderr);
+            let stderr = stderr.trim();
+            Err(audio_backend_missing_hint((!stderr.is_empty()).then_some(stderr)))
+        }
+        Err(e) => Err(format!(
+            "The pkg-config probe for `alsa` could not be run: {e}. Install pkg-config (or pkgconf), \
+             or point PKG_CONFIG at a working one — it is the same lookup alsa-sys's pkg-config \
+             dependency performs."
+        )),
+    }
+}
+
+#[cfg(not(target_os = "linux"))]
+fn audio_backend() -> Result<(), String> {
+    Ok(())
+}
+
 /// Lib, bin and integration tests (examples aren't linked; clippy checked them), then doctests,
 /// which nextest doesn't run.
 ///
@@ -438,7 +494,8 @@ type Stage = fn() -> Result<(), String>;
 
 /// Every stage runs even when an earlier one fails, so one run reports all the problems.
 fn ci() -> Result<(), String> {
-    let stages: [(&str, Stage); 7] = [
+    let stages: [(&str, Stage); 8] = [
+        ("audio backend", audio_backend),
         ("fmt", || run(Command::new(env!("CARGO")).args(["fmt", "--check"]))),
         ("clippy", || run(Command::new(env!("CARGO")).args(["clippy", "--workspace", "--all-targets", "--", "-D", "warnings"]))),
         ("tests", tests),
@@ -459,6 +516,7 @@ fn main() -> ExitCode {
         "assets" => assets(),
         "pdf-deps" => pdf_deps::run(&root()),
         "ci" => ci(),
+        "audio-backend" => audio_backend(),
         "web" => web(&std::env::args().skip(2).collect::<Vec<_>>()),
         "bench" => bench::run(&root(), &std::env::args().skip(2).collect::<Vec<_>>()),
         "ico" => {
@@ -469,7 +527,7 @@ fn main() -> ExitCode {
             let rest: Vec<String> = std::env::args().skip(2).collect();
             version::run(&root(), &rest.iter().map(String::as_str).collect::<Vec<_>>())
         }
-        _ => Err("usage: cargo xtask <layers|assets|pdf-deps|wasm|web [--dev] [--serve PORT]|ico OUT.ico IN.png…|version [set X.Y.Z]|ci|bench [--bin CLI] [--quick] [--project F --comp C] [--compare OLD.jsonl] (--help)>".into()),
+        _ => Err("usage: cargo xtask <layers|assets|pdf-deps|wasm|web [--dev] [--serve PORT]|ico OUT.ico IN.png…|version [set X.Y.Z]|ci|audio-backend|bench [--bin CLI] [--quick] [--project F --comp C] [--compare OLD.jsonl] (--help)>".into()),
     };
     match r {
         Ok(()) => ExitCode::SUCCESS,
@@ -484,3 +542,22 @@ fn main() -> ExitCode {
 pub fn root() -> std::path::PathBuf {
     std::path::Path::new(env!("CARGO_MANIFEST_DIR")).parent().expect("xtask has a parent dir").to_path_buf()
 }
+
+#[cfg(all(test, target_os = "linux"))]
+mod tests {
+    use super::audio_backend_missing_hint;
+
+    #[test]
+    fn alsa_missing_names_the_package_for_each_distro() {
+        let e = audio_backend_missing_hint(None);
+        for want in ["alsa-lib-devel", "libasound2-dev", "alsa-lib", "pkg-config", "PKG_CONFIG_PATH"] {
+            assert!(e.contains(want), "hint lost `{want}`:\n{e}");
+        }
+    }
+
+    #[test]
+    fn alsa_missing_appends_pkg_config_s_own_detail() {
+        let e = audio_backend_missing_hint(Some("Package 'alsa' not found"));
+        assert!(e.contains("pkg-config said: Package 'alsa' not found"), "detail lost:\n{e}");
+    }
+}
diff --git a/xtask/tests/it/audio_probe.rs b/xtask/tests/it/audio_probe.rs
new file mode 100644
index 000000000..d984c7637
--- /dev/null
+++ b/xtask/tests/it/audio_probe.rs
@@ -0,0 +1,126 @@
+//! The Linux audio-backend preflight against fake pkg-config tools.
+//!
+//! The probe resolves its executable through the pkg-config crate, which reads the environment,
+//! so the fake-tool scenarios run the real `xtask audio-backend` binary in a child process with a
+//! controlled environment: `Command::env` changes only the child's environment, so the tests need
+//! no global env mutation and stay parallel-safe.
+
+use std::ffi::OsStr;
+use std::path::PathBuf;
+use std::process::{Command, Output};
+
+/// A scratch directory holding the fake tools for one scenario: `dir` is the child's `PATH`,
+/// `off_path` holds executables reachable only by an explicit `*_PKG_CONFIG` override.
+struct FakeTools {
+    dir: PathBuf,
+    off_path: PathBuf,
+}
+
+impl FakeTools {
+    fn new(tag: &str) -> Self {
+        let base = std::env::temp_dir().join(format!("effectcraft-xtask-audio-{tag}-{}", std::process::id()));
+        let dir = base.join("bin");
+        let off_path = base.join("off-path");
+        std::fs::create_dir_all(&dir).expect("create PATH dir");
+        std::fs::create_dir_all(&off_path).expect("create off-PATH dir");
+        Self { dir, off_path }
+    }
+
+    /// Write a plain (not executable) file.
+    fn file(&self, on_path: bool, name: &str, body: &str) -> PathBuf {
+        let path = if on_path { self.dir.clone() } else { self.off_path.clone() }.join(name);
+        std::fs::write(&path, body).expect("write fake tool");
+        path
+    }
+
+    /// Write an executable shell script.
+    fn script(&self, on_path: bool, name: &str, body: &str) -> PathBuf {
+        use std::os::unix::fs::PermissionsExt;
+        let path = self.file(on_path, name, body);
+        std::fs::set_permissions(&path, std::fs::Permissions::from_mode(0o755)).expect("chmod fake tool");
+        path
+    }
+
+    /// A fake `pkgconf` that answers as alsa 1.2.11 linking -lasound.
+    fn working_pkgconf(&self, on_path: bool) -> PathBuf {
+        self.script(on_path, "pkgconf", "#!/bin/sh\ncase \" $* \" in\n  *\" --modversion \"*) echo 1.2.11 ;;\n  *) echo -lasound ;;\nesac\n")
+    }
+}
+
+impl Drop for FakeTools {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_dir_all(&self.dir);
+        let _ = std::fs::remove_dir_all(&self.off_path);
+    }
+}
+
+/// Run the built `xtask audio-backend` with `dir` as the only `PATH`, the given variables set,
+/// and every variable the probe reads otherwise cleared, so a developer's own environment
+/// cannot leak into the scenario.
+fn run_audio_backend(tools: &FakeTools, set: &[(&str, &OsStr)]) -> Output {
+    Command::new(env!("CARGO_BIN_EXE_xtask"))
+        .arg("audio-backend")
+        .env("PATH", &tools.dir)
+        .env_remove("PKG_CONFIG")
+        .env_remove("PKG_CONFIG_PATH")
+        .env_remove("PKG_CONFIG_LIBDIR")
+        .env_remove("PKG_CONFIG_SYSROOT_DIR")
+        .env_remove("PKG_CONFIG_ALLOW_CROSS")
+        .env_remove("ALSA_NO_PKG_CONFIG")
+        .env_remove("HOST_PKG_CONFIG")
+        .env_remove("TARGET_PKG_CONFIG")
+        .env_remove("HOST")
+        .env_remove("TARGET")
+        .envs(set.iter().copied())
+        .output()
+        .expect("run xtask audio-backend")
+}
+
+#[test]
+fn a_host_with_only_pkgconf_still_finds_alsa() {
+    // The reviewed case: PKG_CONFIG unset, no pkg-config on PATH, only pkgconf. The pkg-config
+    // crate alsa-sys uses falls back to pkgconf, so the stage must stay green.
+    let tools = FakeTools::new("pkgconf-only");
+    tools.working_pkgconf(true);
+    let out = run_audio_backend(&tools, &[]);
+    assert!(out.status.success(), "pkgconf-only host must pass:\n{}", String::from_utf8_lossy(&out.stderr));
+}
+
+#[test]
+fn a_probe_that_runs_and_says_no_names_the_package() {
+    let tools = FakeTools::new("says-no");
+    tools.script(true, "pkg-config", "#!/bin/sh\necho 'Package alsa was not found' >&2\nexit 1\n");
+    let out = run_audio_backend(&tools, &[]);
+    assert!(!out.status.success());
+    let stderr = String::from_utf8_lossy(&out.stderr);
+    for want in ["alsa-lib-devel", "libasound2-dev", "alsa-lib", "pkg-config"] {
+        assert!(stderr.contains(want), "hint lost `{want}`:\n{stderr}");
+    }
+    assert!(stderr.contains("not found"), "pkg-config's own detail should be appended:\n{stderr}");
+}
+
+#[test]
+fn a_probe_that_cannot_run_is_not_alsa_missing() {
+    // PKG_CONFIG names a file that is not an executable; with PKG_CONFIG set the crate does not
+    // fall back to pkgconf, so the lookup fails to launch — reported separately from "missing".
+    let tools = FakeTools::new("cannot-run");
+    let broken = tools.file(true, "not-an-executable", "this is not a program\n");
+    let out = run_audio_backend(&tools, &[("PKG_CONFIG", broken.as_os_str())]);
+    assert!(!out.status.success());
+    let stderr = String::from_utf8_lossy(&out.stderr);
+    assert!(stderr.contains("could not"), "expected the launch-failure error:\n{stderr}");
+    assert!(!stderr.contains("alsa-lib-devel"), "must not read as ALSA missing:\n{stderr}");
+}
+
+#[test]
+fn a_host_scoped_override_selects_that_executable() {
+    // With TARGET and HOST set (build-script style), HOST_PKG_CONFIG wins over the PATH lookup,
+    // and here it is the only working tool — so success proves the override was used.
+    let tools = FakeTools::new("scoped");
+    let good = tools.working_pkgconf(false);
+    let out = run_audio_backend(
+        &tools,
+        &[("HOST", OsStr::new("x86_64-unknown-linux-gnu")), ("TARGET", OsStr::new("x86_64-unknown-linux-gnu")), ("HOST_PKG_CONFIG", good.as_os_str())],
+    );
+    assert!(out.status.success(), "HOST_PKG_CONFIG override must be honored:\n{}", String::from_utf8_lossy(&out.stderr));
+}
diff --git a/xtask/tests/it/main.rs b/xtask/tests/it/main.rs
new file mode 100644
index 000000000..f2c41c738
--- /dev/null
+++ b/xtask/tests/it/main.rs
@@ -0,0 +1,4 @@
+//! xtask's integration tests: one binary, modules in `tests/it/`.
+
+#[cfg(target_os = "linux")]
+mod audio_probe;