diff --git a/crates/engine/src/commands/layer.rs b/crates/engine/src/commands/layer.rs
index b798493b..0832163d 100644
--- a/crates/engine/src/commands/layer.rs
+++ b/crates/engine/src/commands/layer.rs
@@ -417,8 +417,10 @@ fn set_switch_others(s: &mut Session, cid: ItemId, ids: &[LayerId], name: &str,
         let applies = |l: &Layer| match name {
             "audio" => l.props.sub("audio").is_some(),
             "lock" | "locked" => true,
-            // Nulls have a Video switch too (it hides their outline in the viewer).
-            "video" | "eye" => (l.source.is_av() || matches!(l.source, LayerSource::Null)) && !mattes.contains(&l.id),
+            // Every layer has a Video switch (it hides a null's outline in the viewer and turns a
+            // camera or light off), as the Timeline's eye cell shows; track mattes keep theirs off
+            // by design.
+            "video" | "eye" => !mattes.contains(&l.id),
             _ => l.source.is_av() && !mattes.contains(&l.id),
         };
         let mut alone = true;
diff --git a/crates/engine/src/commands/layer_menu.rs b/crates/engine/src/commands/layer_menu.rs
index cdc1dae4..0a044937 100644
--- a/crates/engine/src/commands/layer_menu.rs
+++ b/crates/engine/src/commands/layer_menu.rs
@@ -114,10 +114,10 @@ fn frame_blending(s: &mut Session, p: &Value) -> Result<Value> {
 fn hide_other_video(s: &mut Session, p: &Value) -> Result<Value> {
     let (cid, ids) = layers_p(s, p)?;
     s.edit("Hide Other Video", None, |proj, _| {
-        for l in proj.comp_mut(cid).ok_or(EngineError::NoComp)?.layers.iter_mut() {
-            if !ids.contains(&l.id) && (l.source.is_av() || matches!(l.source, LayerSource::Null)) {
-                l.switches.video = false;
-            }
+        // Every layer has a Video switch (nulls, cameras and lights included, as the Timeline's
+        // eye cell shows): the selection stays shown.
+        for l in proj.comp_mut(cid).ok_or(EngineError::NoComp)?.layers.iter_mut().filter(|l| !ids.contains(&l.id)) {
+            l.switches.video = false;
         }
         Ok(())
     })?;
diff --git a/crates/engine/src/tests_menu_cmds.rs b/crates/engine/src/tests_menu_cmds.rs
index fd19300d..5131bf3f 100644
--- a/crates/engine/src/tests_menu_cmds.rs
+++ b/crates/engine/src/tests_menu_cmds.rs
@@ -111,6 +111,29 @@ fn set_switch_others() {
     assert!(s.execute("layer.setSwitch", json!({"layers": [c], "switch": "nope", "others": true})).is_err());
 }
 
+/// The Video switch has a cell on every layer's row, cameras and lights included, so Alt-clicking
+/// it (and Hide Other Video) takes them along with the rest.
+#[test]
+fn video_others_takes_cameras_and_lights() {
+    let mut s = comp();
+    let a = solid(&mut s, "#ff0000");
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    let light = s.execute("layer.newLight", json!({"kind": "Point"})).unwrap()["layer"].as_u64().unwrap();
+    let get = |s: &Session, f: fn(&effectcraft_project::Layer) -> bool| [a, cam, light].map(|l| f(&layer(s, l)));
+    // The camera and the light are hidden: Alt-click on the solid's eye brings them back, since
+    // they stand apart with it, and the next Alt-click hides them with every other layer.
+    s.execute("layer.setSwitch", json!({"layers": [cam, light], "switch": "video", "value": false})).unwrap();
+    s.execute("layer.setSwitch", json!({"layers": [a], "switch": "video", "others": true})).unwrap();
+    assert_eq!(get(&s, |l| l.switches.video), [true; 3]);
+    s.execute("layer.setSwitch", json!({"layers": [a], "switch": "video", "others": true})).unwrap();
+    assert_eq!(get(&s, |l| l.switches.video), [true, false, false]);
+    // Hide Other Video takes them too.
+    s.execute("layer.showAllVideo", json!({})).unwrap();
+    assert_eq!(get(&s, |l| l.switches.video), [true; 3]);
+    s.execute("layer.hideOtherVideo", json!({"layers": [a]})).unwrap();
+    assert_eq!(get(&s, |l| l.switches.video), [true, false, false]);
+}
+
 /// A null's Video switch (the eye) works like any layer's, as in After Effects: it toggles,
 /// Alt-click and Hide Other Video take nulls along, and its children still follow it while it is
 /// hidden (parenting ignores the eye).
diff --git a/crates/ui-egui/src/panels/timeline.rs b/crates/ui-egui/src/panels/timeline.rs
index 74fc84b2..0d5a3941 100644
--- a/crates/ui-egui/src/panels/timeline.rs
+++ b/crates/ui-egui/src/panels/timeline.rs
@@ -8,7 +8,7 @@
 
 use effectcraft_engine::color::BlendMode;
 use effectcraft_engine::keyframe::{Interp, Value};
-use effectcraft_engine::project::{Comp, GroupKind, ItemId, Layer, LayerId, LayerSource, MatteKind, Node, ParamUi, PropGroup, Property};
+use effectcraft_engine::project::{Comp, GroupKind, ItemId, Layer, LayerId, LayerSource, MatteKind, Node, ParamUi, Project, PropGroup, Property};
 use effectcraft_engine::render::EvalCtx;
 use effectcraft_engine::time::Tick;
 use egui::{Align2, Color32, Pos2, Rect, Sense, Stroke, StrokeKind, pos2, vec2};
@@ -1314,6 +1314,39 @@ 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.
+fn edited_layers(layer: LayerId, selected: &[LayerId]) -> Vec<u64> {
+    if selected.contains(&layer) { selected.iter().map(|l| l.0).collect() } else { vec![layer.0] }
+}
+
+/// Whether the Timeline shows switch `name`'s cell on `layer`'s row (A/V Features and Switches
+/// columns): a layer that has no such cell isn't one a click gives the switch to either.
+fn switch_applies(layer: &Layer, name: &str, project: &Project) -> bool {
+    match name {
+        "video" | "lock" | "shy" => true,
+        "audio" => layer.props.sub("audio").is_some(),
+        "solo" | "quality" | "motionBlur" | "adjustment" => layer.source.is_av(),
+        "collapse" => collapse_applies(layer, project),
+        "fx" => layer.effects().is_some_and(|f| !f.children.is_empty()),
+        "frameBlend" => matches!(layer.source, LayerSource::Footage { .. } | LayerSource::Comp { .. }),
+        "threeD" => layer.source.is_av() || matches!(layer.source, LayerSource::Null),
+        _ => true,
+    }
+}
+
+/// The layers a click on the `name` switch of `layer`'s row acts on: [`edited_layers`] without
+/// the layers the switch doesn't apply to.
+fn switch_targets(comp: &Comp, project: &Project, selected: &[LayerId], layer: u64, name: &str) -> Vec<u64> {
+    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> {
+    edited_layers(layer, selected).into_iter().filter(|l| comp.layer(LayerId(*l)).is_some_and(|l| l.source.is_av())).collect()
+}
+
 /// A layer's switch (A/V Features and Switches columns) in `row`, with the
 /// [`switch_gesture`].
 #[allow(clippy::too_many_arguments)]
@@ -1328,20 +1361,29 @@ fn layer_switch(
     layer: u64,
     name: &'static str,
     others: bool,
+    comp: &Comp,
+    project: &Project,
+    selected: &[LayerId],
     actions: &mut Vec<(String, serde_json::Value)>,
 ) {
     let resp = widgets::icon_toggle(ui, br, icon, on, t, id, Sense::click_and_drag());
     // Alt-click on an A/V feature sets the layer apart: the other layers go off (or locked),
-    // and come back on the next Alt-click.
+    // and come back on the next Alt-click. With several layers selected, the whole selection is
+    // set apart.
     if others && resp.is_pointer_button_down_on() && ui.input(|i| i.pointer.primary_pressed() && i.modifiers.alt) {
-        actions.push(("layer.setSwitch".into(), json!({"layers": [layer], "switch": name, "others": true})));
+        let layers = edited_layers(LayerId(layer), selected);
+        actions.push(("layer.setSwitch".into(), json!({"layers": layers, "switch": name, "others": true})));
         return;
     }
+    // A press on a selected layer's switch gives the switch to every selected layer, as in After
+    // Effects; the targets are picked when the press happens, never while the row is drawn.
     if let Some((value, merge)) = switch_gesture(ui, &resp, row, name, on) {
-        actions.push(("layer.setSwitch".into(), json!({"layers": [layer], "switch": name, "value": value, "merge": merge})));
+        let layers = switch_targets(comp, project, selected, layer, name);
+        actions.push(("layer.setSwitch".into(), json!({"layers": layers, "switch": name, "value": value, "merge": merge})));
     } else if resp.clicked() && !resp.clicked_by(egui::PointerButton::Primary) {
         // Keyboard or accessibility activation (a pointer press was handled above).
-        actions.push(("layer.setSwitch".into(), json!({"layers": [layer], "switch": name})));
+        let layers = switch_targets(comp, project, selected, layer, name);
+        actions.push(("layer.setSwitch".into(), json!({"layers": layers, "switch": name, "value": !on})));
     }
 }
 
@@ -2000,10 +2042,10 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                 // as in After Effects: it hides a null's outline in the viewer and turns a camera or
                 // light off.
                 let av_items: [(Icon, bool, &str, bool); 4] = [
-                    (Icon::Eye, sw.video, "video", true),
-                    (Icon::Speaker, sw.audio, "audio", layer.props.sub("audio").is_some()),
-                    (Icon::Solo, sw.solo, "solo", layer.source.is_av()),
-                    (Icon::Lock, sw.locked, "lock", true),
+                    (Icon::Eye, sw.video, "video", switch_applies(layer, "video", &app.session.project)),
+                    (Icon::Speaker, sw.audio, "audio", switch_applies(layer, "audio", &app.session.project)),
+                    (Icon::Solo, sw.solo, "solo", switch_applies(layer, "solo", &app.session.project)),
+                    (Icon::Lock, sw.locked, "lock", switch_applies(layer, "lock", &app.session.project)),
                 ];
                 for (i, (icon, on, name, applicable)) in av_items.into_iter().enumerate() {
                     let br = Rect::from_center_size(pos2(cw.av + 10.0 + 18.0 * i as f32, cy), vec2(15.0, 15.0));
@@ -2011,7 +2053,22 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                         continue;
                     }
                     lp.rect_filled(br.shrink(0.5), 1.0, t.switch_well);
-                    layer_switch(ui, &t, r, br, icon, on, egui::Id::new(("av", layer.id.0, i)), layer.id.0, name, true, &mut actions);
+                    layer_switch(
+                        ui,
+                        &t,
+                        r,
+                        br,
+                        icon,
+                        on,
+                        egui::Id::new(("av", layer.id.0, i)),
+                        layer.id.0,
+                        name,
+                        true,
+                        &comp,
+                        &app.session.project,
+                        &selected,
+                        &mut actions,
+                    );
                     app.auto.add(&format!("timeline.layer.{}.{name}", layer.id.0), br, name);
                 }
                 // Label swatch.
@@ -2026,7 +2083,7 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                         widgets::open_popup(ui, pop);
                     }
                     if let Some(lab) = widgets::label_popup(ui, pop, lr.left_bottom(), layer.label, |l| app.session.prefs.label_name(l), &t) {
-                        actions.push(("edit.label".into(), json!({"layers": [layer.id.0], "label": lab.name()})));
+                        actions.push(("edit.label".into(), json!({"layers": edited_layers(layer.id, &selected), "label": lab.name()})));
                     }
                 }
                 if vis.num {
@@ -2122,19 +2179,24 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                 layer_context_menu(&row_resp, &comp, layer, &selected, LayerMenuCaps::of(&app.session.project, layer), &mut app.auto, &mut actions);
                 // Switches.
                 let sws: [(Icon, bool, &str, bool); 8] = [
-                    (Icon::Shy, sw.shy, "shy", true),
-                    (Icon::Collapse, sw.collapse, "collapse", collapse_applies(layer, &app.session.project)),
-                    (Icon::Quality, sw.quality == effectcraft_engine::project::Quality::Best, "quality", layer.source.is_av()),
-                    (Icon::Fx, sw.effects, "fx", layer.effects().is_some_and(|f| !f.children.is_empty())),
+                    (Icon::Shy, sw.shy, "shy", switch_applies(layer, "shy", &app.session.project)),
+                    (Icon::Collapse, sw.collapse, "collapse", switch_applies(layer, "collapse", &app.session.project)),
+                    (
+                        Icon::Quality,
+                        sw.quality == effectcraft_engine::project::Quality::Best,
+                        "quality",
+                        switch_applies(layer, "quality", &app.session.project),
+                    ),
+                    (Icon::Fx, sw.effects, "fx", switch_applies(layer, "fx", &app.session.project)),
                     (
                         Icon::FrameBlend,
                         sw.frame_blend != effectcraft_engine::project::FrameBlend::Off,
                         "frameBlend",
-                        matches!(layer.source, LayerSource::Footage { .. } | LayerSource::Comp { .. }),
+                        switch_applies(layer, "frameBlend", &app.session.project),
                     ),
-                    (Icon::MotionBlur, sw.motion_blur, "motionBlur", layer.source.is_av()),
-                    (Icon::Adjustment, sw.adjustment, "adjustment", layer.source.is_av()),
-                    (Icon::Cube, layer.is_3d(), "threeD", layer.source.is_av() || matches!(layer.source, LayerSource::Null)),
+                    (Icon::MotionBlur, sw.motion_blur, "motionBlur", switch_applies(layer, "motionBlur", &app.session.project)),
+                    (Icon::Adjustment, sw.adjustment, "adjustment", switch_applies(layer, "adjustment", &app.session.project)),
+                    (Icon::Cube, layer.is_3d(), "threeD", switch_applies(layer, "threeD", &app.session.project)),
                 ];
                 for (i, (icon, on, name, applicable)) in sws.into_iter().enumerate() {
                     if !applicable || !vis.switches {
@@ -2142,7 +2204,22 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                     }
                     let br = Rect::from_center_size(pos2(cw.switches + SW * i as f32 + SW / 2.0, cy), vec2(16.0, 16.0));
                     lp.rect_filled(br.shrink(1.0), 1.0, t.switch_well);
-                    layer_switch(ui, &t, r, br, icon, on, egui::Id::new(("sw", layer.id.0, i)), layer.id.0, name, false, &mut actions);
+                    layer_switch(
+                        ui,
+                        &t,
+                        r,
+                        br,
+                        icon,
+                        on,
+                        egui::Id::new(("sw", layer.id.0, i)),
+                        layer.id.0,
+                        name,
+                        false,
+                        &comp,
+                        &app.session.project,
+                        &selected,
+                        &mut actions,
+                    );
                     app.auto.add(&format!("timeline.layer.{}.switch.{name}", layer.id.0), br, name);
                 }
                 // Modes.
@@ -2159,11 +2236,21 @@ pub fn show(app: &mut EffectcraftApp, ui: &mut egui::Ui, rect: Rect) {
                         .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": [layer.id.0], "mode": opts[i]})));
+                        actions.push(("layer.setBlendMode".into(), json!({"layers": mode_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");
                     if widgets::checkbox(ui, tr, layer.preserve_transparency, &t, egui::Id::new(("pt", layer.id.0))).clicked() {
-                        actions.push(("layer.setSwitch".into(), json!({"layers": [layer.id.0], "switch": "preserveTransparency"})));
+                        // The click gives the selection the state the clicked row toggles to,
+                        // whatever the first selected layer's value (as the switches do).
+                        actions.push((
+                            "layer.setSwitch".into(),
+                            json!({
+                                "layers": mode_targets(&comp, layer.id, &selected),
+                                "switch": "preserveTransparency",
+                                "value": !layer.preserve_transparency
+                            }),
+                        ));
                     }
                     // Track matte: layer picker + kind.
                     let mr = Rect::from_min_size(pos2(cw.trkmat + 2.0, cy - 9.0), vec2(104.0, 18.0));
diff --git a/crates/ui-egui/tests/it/main.rs b/crates/ui-egui/tests/it/main.rs
index a6903854..7dc15334 100644
--- a/crates/ui-egui/tests/it/main.rs
+++ b/crates/ui-egui/tests/it/main.rs
@@ -7,6 +7,7 @@ mod ui_agent_audit;
 mod ui_angles;
 mod ui_audio_scrub;
 mod ui_azerty_shortcuts;
+mod ui_batch_switches;
 mod ui_blank_context_menus;
 mod ui_camera_tracker;
 mod ui_character_eyedropper;
diff --git a/crates/ui-egui/tests/it/ui_batch_switches.rs b/crates/ui-egui/tests/it/ui_batch_switches.rs
new file mode 100644
index 00000000..407ac194
--- /dev/null
+++ b/crates/ui-egui/tests/it/ui_batch_switches.rs
@@ -0,0 +1,244 @@
+//! A Timeline row control clicked on one of several selected layers applies to the whole
+//! selection (#1849), as in After Effects: the A/V Features and Switches columns, the label
+//! swatch and the Modes column. The engine commands already took several layers; the row
+//! controls used to pass the clicked layer alone.
+
+use effectcraft_engine::Session;
+use effectcraft_engine::color::{BlendMode, Label};
+use effectcraft_engine::project::{Layer, LayerId, Switches};
+use effectcraft_ui_egui::EffectcraftApp;
+use egui::{Event, Modifiers, Pos2, Rect, pos2, vec2};
+use egui_kittest::Harness;
+use egui_kittest::kittest::Queryable;
+use serde_json::json;
+
+/// Comp "Main" with solids A (top) to D (bottom); returns their ids top to bottom.
+fn harness() -> (Harness<'static, EffectcraftApp>, Vec<u64>) {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Main", "width": 320, "height": 180, "frameRate": 30, "duration": 4})).unwrap();
+    let mut ids: Vec<u64> = ["D", "C", "B", "A"]
+        .iter()
+        .map(|name| s.execute("layer.newSolid", json!({"name": name, "color": "#406080"})).unwrap()["layer"].as_u64().unwrap())
+        .collect();
+    ids.reverse();
+    s.execute("edit.deselectAll", json!({})).unwrap();
+    let mut h = Harness::builder().with_size(vec2(1600.0, 1000.0)).build_eframe(|_| EffectcraftApp::new(s));
+    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}")).clone();
+    Rect::from_min_size(pos2(e.rect[0], e.rect[1]), vec2(e.rect[2], e.rect[3]))
+}
+
+/// Press on `from`, move to `to` in `steps`, release there.
+fn drag(h: &mut Harness<'_, EffectcraftApp>, from: Pos2, to: Pos2, steps: u32) {
+    h.event(Event::PointerMoved(from));
+    h.step();
+    h.event(Event::PointerButton { pos: from, button: egui::PointerButton::Primary, pressed: true, modifiers: Modifiers::NONE });
+    h.step();
+    for k in 1..=steps {
+        h.event(Event::PointerMoved(from + (to - from) * (k as f32 / steps as f32)));
+        h.step();
+    }
+    h.event(Event::PointerButton { pos: to, button: egui::PointerButton::Primary, pressed: false, modifiers: Modifiers::NONE });
+    h.run_steps(3);
+}
+
+/// A click on the Timeline control `id`.
+fn click(h: &mut Harness<'_, EffectcraftApp>, id: &str) {
+    let p = rect(h, id).center();
+    drag(h, p, p, 1);
+}
+
+/// A click at `p` (a menu entry, found by its label).
+fn click_at(h: &mut Harness<'_, EffectcraftApp>, p: Pos2) {
+    drag(h, p, p, 1);
+}
+
+fn alt_click(h: &mut Harness<'_, EffectcraftApp>, id: &str) {
+    let p = rect(h, id).center();
+    let modifiers = Modifiers::ALT;
+    h.event(Event::PointerMoved(p));
+    h.event(Event::ModifiersChanged(modifiers));
+    h.step();
+    h.event(Event::PointerButton { pos: p, button: egui::PointerButton::Primary, pressed: true, modifiers });
+    h.step();
+    h.event(Event::PointerButton { pos: p, button: egui::PointerButton::Primary, pressed: false, modifiers });
+    h.event(Event::ModifiersChanged(Modifiers::NONE));
+    h.run_steps(3);
+}
+
+/// Select `ids` in the Timeline, as a Shift range or a Cmd toggle would.
+fn select(h: &mut Harness<'_, EffectcraftApp>, ids: &[u64]) {
+    h.state_mut().session.execute("layer.select", json!({"layers": ids})).unwrap();
+    h.run_steps(2);
+}
+
+/// The state of switch `f` on each layer of `ids`, top to bottom.
+fn states(h: &Harness<'_, EffectcraftApp>, ids: &[u64], f: fn(&Layer) -> bool) -> Vec<bool> {
+    let comp = h.state().session.active_comp().unwrap();
+    ids.iter().map(|id| f(comp.layer(LayerId(*id)).unwrap())).collect()
+}
+
+fn switches(h: &Harness<'_, EffectcraftApp>, id: u64) -> Switches {
+    h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().switches.clone()
+}
+
+fn locked(l: &Layer) -> bool {
+    l.switches.locked
+}
+
+fn video(l: &Layer) -> bool {
+    l.switches.video
+}
+
+fn three_d(l: &Layer) -> bool {
+    l.switches.three_d
+}
+
+fn solo(l: &Layer) -> bool {
+    l.switches.solo
+}
+
+fn shy(l: &Layer) -> bool {
+    l.switches.shy
+}
+
+fn motion_blur(l: &Layer) -> bool {
+    l.switches.motion_blur
+}
+
+fn preserved(l: &Layer) -> bool {
+    l.preserve_transparency
+}
+
+/// #1849: a click on the Lock, 3D, Solo, Shy or Motion Blur switch of a selected layer gives the
+/// switch to every selected layer, in one undo step.
+#[test]
+fn switches_on_a_selected_row_set_the_whole_selection() {
+    let (mut h, ids) = harness();
+    select(&mut h, &[ids[0], ids[2]]);
+
+    let steps = h.state().session.history.undo.len();
+    click(&mut h, &format!("timeline.layer.{}.lock", ids[0]));
+    assert_eq!(states(&h, &ids, locked), [true, false, true, false]);
+    assert_eq!(h.state().session.history.undo.len(), steps + 1, "one undo step");
+    h.state_mut().session.execute("edit.undo", json!({})).unwrap();
+    h.run_steps(2);
+    assert_eq!(states(&h, &ids, locked), [false; 4]);
+
+    click(&mut h, &format!("timeline.layer.{}.switch.threeD", ids[0]));
+    assert_eq!(states(&h, &ids, three_d), [true, false, true, false]);
+    // The switch of the other selected layer acts the same way.
+    click(&mut h, &format!("timeline.layer.{}.solo", ids[2]));
+    assert_eq!(states(&h, &ids, solo), [true, false, true, false]);
+    click(&mut h, &format!("timeline.layer.{}.switch.shy", ids[2]));
+    assert_eq!(states(&h, &ids, shy), [true, false, true, false]);
+    click(&mut h, &format!("timeline.layer.{}.switch.motionBlur", ids[0]));
+    assert_eq!(states(&h, &ids, motion_blur), [true, false, true, false]);
+    // A second click turns both off again, whatever their own state.
+    click(&mut h, &format!("timeline.layer.{}.switch.threeD", ids[2]));
+    assert_eq!(states(&h, &ids, three_d), [false; 4]);
+}
+
+/// A switch on a row that isn't selected still changes that layer alone, and leaves the
+/// selection.
+#[test]
+fn a_switch_on_an_unselected_row_sets_that_layer_only() {
+    let (mut h, ids) = harness();
+    select(&mut h, &[ids[0], ids[2]]);
+    click(&mut h, &format!("timeline.layer.{}.lock", ids[1]));
+    assert_eq!(states(&h, &ids, locked), [false, true, false, false]);
+    assert_eq!(h.state().session.state.selected_layers, vec![LayerId(ids[0]), LayerId(ids[2])]);
+}
+
+/// The targets skip the selected layers a switch doesn't apply to: 3D reaches a null but not a
+/// camera (3D by kind), the Effect switch not a layer without effects.
+#[test]
+fn switch_targets_skip_the_layers_the_switch_does_not_apply_to() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Main", "width": 320, "height": 180, "frameRate": 30, "duration": 4})).unwrap();
+    let solid = s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    let null = s.execute("layer.newNull", json!({"name": "Ctrl"})).unwrap()["layer"].as_u64().unwrap();
+    let cam = s.execute("layer.newCamera", json!({})).unwrap()["layer"].as_u64().unwrap();
+    s.execute("effect.apply", json!({"effect": "ec.blur.gaussian", "layers": [solid]})).unwrap();
+    s.execute("edit.deselectAll", json!({})).unwrap();
+    let mut h = Harness::builder().with_size(vec2(1600.0, 1000.0)).build_eframe(|_| EffectcraftApp::new(s));
+    h.run_steps(3);
+    select(&mut h, &[solid, null, cam]);
+
+    click(&mut h, &format!("timeline.layer.{solid}.switch.threeD"));
+    assert!(switches(&h, solid).three_d && switches(&h, null).three_d, "3D reaches the null");
+    assert!(!switches(&h, cam).three_d, "a camera is 3D by kind, its own switch stays off");
+
+    click(&mut h, &format!("timeline.layer.{solid}.switch.fx"));
+    assert!(!switches(&h, solid).effects, "the Effect switch reaches the layer that has an effect");
+    assert!(switches(&h, null).effects && switches(&h, cam).effects, "no effects, no Effect switch");
+}
+
+/// Alt-click on an A/V feature sets the selected layers apart (the others off), and the next
+/// Alt-click brings the others back — with several layers, the whole selection stands apart.
+#[test]
+fn alt_click_sets_the_selected_layers_apart() {
+    let (mut h, ids) = harness();
+    select(&mut h, &[ids[0], ids[2]]);
+    alt_click(&mut h, &format!("timeline.layer.{}.video", ids[0]));
+    assert_eq!(states(&h, &ids, video), [true, false, true, false]);
+    alt_click(&mut h, &format!("timeline.layer.{}.video", ids[0]));
+    assert_eq!(states(&h, &ids, video), [true; 4]);
+}
+
+/// The label swatch menu of a selected layer sets the label of every selected layer.
+#[test]
+fn the_label_menu_sets_the_selections_label() {
+    let (mut h, ids) = harness();
+    select(&mut h, &[ids[0], ids[2]]);
+    let green = h.state().session.prefs.label_name(Label::Green);
+    click(&mut h, &format!("timeline.layer.{}.label", ids[0]));
+    let entry = h.query_by_label(&green).expect("the label menu is open").rect();
+    click_at(&mut h, entry.center());
+    let label = |id: u64| h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().label;
+    assert_eq!([label(ids[0]), label(ids[1]), label(ids[2]), label(ids[3])], [Label::Green, Label::Red, Label::Green, Label::Red]);
+}
+
+/// The Modes column: the Blending Mode menu and the Preserve Transparency checkbox of a selected
+/// layer set both selected layers, one undo step each.
+#[test]
+fn the_modes_column_sets_the_whole_selection() {
+    let (mut h, ids) = harness();
+    h.state_mut().ui.timeline.show_modes = true;
+    h.run_steps(3);
+    select(&mut h, &[ids[0], ids[2]]);
+
+    click(&mut h, &format!("timeline.layer.{}.mode", ids[0]));
+    let entry = h.query_by_label("Multiply").expect("the blend mode menu is open").rect();
+    click_at(&mut h, entry.center());
+    let mode = |id: u64| h.state().session.active_comp().unwrap().layer(LayerId(id)).unwrap().blend_mode;
+    assert_eq!([mode(ids[0]), mode(ids[1]), mode(ids[2]), mode(ids[3])], [BlendMode::Multiply, BlendMode::Normal, BlendMode::Multiply, BlendMode::Normal]);
+
+    click(&mut h, &format!("timeline.layer.{}.preserveTransparency", ids[0]));
+    assert_eq!(states(&h, &ids, preserved), [true, false, true, false]);
+
+    h.state_mut().session.execute("edit.undo", json!({})).unwrap();
+    h.run_steps(2);
+    assert_eq!(states(&h, &ids, preserved), [false; 4], "one undo step put both back");
+}
+
+/// Preserve Transparency toggles from the row it is clicked on, not from the first selected layer:
+/// A on and C off, clicking C's box turns both on.
+#[test]
+fn preserve_transparency_toggles_from_the_clicked_row() {
+    let (mut h, ids) = harness();
+    h.state_mut().ui.timeline.show_modes = true;
+    h.run_steps(3);
+    h.state_mut().session.execute("layer.setSwitch", json!({"layers": [ids[0]], "switch": "preserveTransparency", "value": true})).unwrap();
+    h.run_steps(2);
+    select(&mut h, &[ids[0], ids[2]]);
+    click(&mut h, &format!("timeline.layer.{}.preserveTransparency", ids[2]));
+    assert_eq!(states(&h, &ids, preserved), [true, false, true, false]);
+    // The next click turns both off again.
+    click(&mut h, &format!("timeline.layer.{}.preserveTransparency", ids[2]));
+    assert_eq!(states(&h, &ids, preserved), [false; 4]);
+}
diff --git a/docs/agents.md b/docs/agents.md
index b2589a7a..04f09a2e 100644
--- a/docs/agents.md
+++ b/docs/agents.md
@@ -595,6 +595,12 @@ Extension points and the bundled extensions: [plugins.md](plugins.md).
   properties, FF missing effects, EE Expressions, LL Waveform, UU everything changed from its
   default. Shift+key adds or removes a set; the same key again hides it; Ctrl/Cmd+` twirls the
   selected layers open or closed. With no layer selected they apply to every layer.
+* A row control clicked on one of several selected layers applies to every selected layer, as in
+  After Effects: the A/V switches (video, audio, solo, lock), the Switches column (shy, collapse,
+  quality, fx, frame blending, motion blur, adjustment, 3D), the label swatch and the Modes column
+  (blending mode, Preserve Transparency), one undo step, with the layers the switch doesn't apply
+  to left out. A control on an unselected row changes that layer alone; Alt-clicking an A/V feature
+  still sets the selected layers apart from the rest.
 * `keys.toggleTransform {"layers"?: [...], "prop": "position"}` (Alt+Shift+A/P/S/R/T) adds or
   removes a keyframe at the current time on that Transform property of each layer, in one undo
   step (separated X/Y/Z Position; Orientation and X/Y/Z Rotation on 3D layers).
diff --git a/docs/ui-parity.md b/docs/ui-parity.md
index ccce70e0..f2956918 100644
--- a/docs/ui-parity.md
+++ b/docs/ui-parity.md
@@ -17,7 +17,7 @@ feel and platform differences, and the 26.x interface changes are not in yet.
 |---|---|---:|---|
 | Menu bar | After Effects' menus, order, submenus and labels; native on macOS; keyboard-operable in-window bar | 95% | 587 entries in `crates/engine/src/menus.rs`; Adobe-service entries omitted by design; `ui_menus` tests (#279) |
 | Panels and workspaces | Every After Effects panel; all standard workspaces; drag-to-dock, tabs, floating panels, maximise | 75% | `ui_tabs`, `ui_panels`; panels move into their own native windows on any screen (#486 open: no dragging tabs between those windows); #302, #301 and #320 (docking, stacked-panel headers, workspace persistence) are closed |
-| Timeline | Switches, modes, parent & link, twirl-downs, reveal shortcuts (U, UU, P, S, R, T, A, E, M, F, Alt+Shift…), pick whips, graph editor, work area, markers | 75% | `ui_keyframes`, `ui_timeline_*`; expand precomps in place (#601); #456, #457, #569 and #355 (Graph Editor jitter and buttons, negative rotation, bulk keyframing) are closed; Proportional Scrubbing (26.2: Ctrl+Alt / Cmd+Opt scrub of hot text spreads the change over the selected layers by selection order, #770) matched for layers selected as a whole, not yet for individually selected properties; every layer has the Video switch, nulls, cameras and lights included (a null with its eye off has no box or handles in the viewer and isn't picked there) |
+| Timeline | Switches, modes, parent & link, twirl-downs, reveal shortcuts (U, UU, P, S, R, T, A, E, M, F, Alt+Shift…), pick whips, graph editor, work area, markers | 75% | `ui_keyframes`, `ui_timeline_*`; expand precomps in place (#601); #456, #457, #569 and #355 (Graph Editor jitter and buttons, negative rotation, bulk keyframing) are closed; Proportional Scrubbing (26.2: Ctrl+Alt / Cmd+Opt scrub of hot text spreads the change over the selected layers by selection order, #770) matched for layers selected as a whole, not yet for individually selected properties; every layer has the Video switch, nulls, cameras and lights included (a null with its eye off has no box or handles in the viewer and isn't picked there); a row control (a switch, the label swatch, a Modes cell) clicked on one of several selected layers acts on the whole selection, with the layers the switch doesn't apply to left out (#1849) |
 | Composition viewer | Selection, handles with direction-aware cursors, rulers, guides, grids, snapping, channels, exposure, region of interest, snapshots, 3D views, Spacebar hand | 70% | `ui_viewer`, `ui_viewers`; Cmd/Ctrl +/− doesn't zoom (#570); anchor point grab on Linux (#492); #352 (snapping) is closed; no 3D transform gizmos (#392, #347); percentage guides (26.5) exist as View ▸ Add Percentage Guide and Convert Guides to Percentage / Pixels (a guide stores a percent of the comp, so it follows comp-size changes; behaviour inferred from the release note, not compared with After Effects); Copy Frame to Clipboard (26.3) is in the Composition menu and the viewer's context menu |
 | Tools panel | All After Effects tools; long-press flyouts; Tool Creates Shape / Mask; Fill / Stroke options | 80% | #213, #227 fixed; #553 (pen and vertex tools on motion paths) is closed |
 | Nudging and modifiers | Arrow nudge (1 px, Shift 10 px), Alt/Option duplicates and slips, Shift constrains | 75% | #290 nudging fixed; #491 (Linux multi-layer edits) is closed |