diff --git a/crates/ui-egui/src/panels/library_panel.rs b/crates/ui-egui/src/panels/library_panel.rs
index 18a4a93eb..409020e3b 100644
--- a/crates/ui-egui/src/panels/library_panel.rs
+++ b/crates/ui-egui/src/panels/library_panel.rs
@@ -826,661 +826,4 @@ pub(crate) fn library_items(ui: &mut Ui, libs: &[LibraryRef], checked: &dyn Fn(&
 }
 
 #[cfg(test)]
-mod tests {
-    use egui::{Event, Modifiers, PointerButton, Pos2, vec2};
-    use serde_json::Value;
-    use vectorcraft_color::Paint;
-    use vectorcraft_engine::Session;
-
-    use super::*;
-    use crate::panels::swatches::SwatchLibraries;
-
-    fn app() -> VectorcraftApp {
-        let mut app = VectorcraftApp::new(Session::new(), Default::default());
-        app.run("file.new", json!({"width": 200, "height": 200})).unwrap();
-        app
-    }
-
-    fn context() -> egui::Context {
-        let ctx = egui::Context::default();
-        crate::theme::install_fonts(&ctx);
-        ctx
-    }
-
-    /// One frame of the library panel with `events` and `modifiers` held.
-    fn frame(app: &mut VectorcraftApp, ctx: &egui::Context, events: Vec<Event>, modifiers: Modifiers, time: f64) {
-        let screen_rect = Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0)));
-        let events = std::iter::once(Event::ModifiersChanged(modifiers)).chain(events).collect();
-        let input = egui::RawInput { events, time: Some(time), screen_rect, ..Default::default() };
-        let mut out = ctx.run_ui(input, |ui| show_window(app, ui.ctx()));
-        out.textures_delta.clear();
-    }
-
-    /// The panel opened last.
-    fn shown(app: &VectorcraftApp) -> String {
-        last_open(&app.ui).expect("a library panel is open").panel()
-    }
-
-    /// Click the tile or row of `name` in the panel opened last with `modifiers` (frames from
-    /// `time` to `time + 0.5`; a new window takes a sizing frame first).
-    fn click(app: &mut VectorcraftApp, ctx: &egui::Context, name: &str, modifiers: Modifiers, time: f64) {
-        frame(app, ctx, vec![], Modifiers::NONE, time);
-        frame(app, ctx, vec![], Modifiers::NONE, time + 0.25);
-        let at = ctx.read_response(tile_id(&shown(app), name)).unwrap_or_else(|| panic!("no tile for {name}")).rect.center();
-        let button = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers };
-        frame(app, ctx, vec![Event::PointerMoved(at), button(true), button(false)], modifiers, time + 0.5);
-    }
-
-    fn undo_len(app: &VectorcraftApp) -> usize {
-        app.session.doc().unwrap().history.undo.len()
-    }
-
-    #[test]
-    fn clicking_a_library_swatch_adds_and_applies_it_in_one_step() {
-        let mut app = app();
-        let ctx = context();
-        let r = app.run("window.swatchLibrary", json!({"library": "Pastels"})).unwrap();
-        assert_eq!((r["open"].as_str(), r["count"].as_u64(), r["panel"].as_str()), (Some("pastels"), Some(24), Some("library:swatches:pastels")));
-        assert_eq!(last_open(&app.ui).map(|p| (p.kind.as_str(), p.id.as_str())), Some(("swatches", "pastels")));
-        let undo = undo_len(&app);
-        click(&mut app, &ctx, "Pastel Teal", Modifiers::NONE, 0.0);
-        let d = &app.session.doc().unwrap().doc;
-        let added = d.swatch("Pastel Teal").expect("added to the document");
-        assert_eq!(app.session.paint.fill, Paint::solid(added.paint.color().unwrap()), "applied to the fill");
-        assert_eq!(undo_len(&app), undo + 1);
-        // Alt-click paints the stroke (the inactive proxy).
-        click(&mut app, &ctx, "Soft Blue", Modifiers::ALT, 2.0);
-        let blue = app.session.doc().unwrap().doc.swatch("Soft Blue").and_then(|w| w.paint.color()).unwrap();
-        assert_eq!(app.session.paint.stroke.color(), Some(blue));
-        assert!(app.session.fill_active, "Alt keeps the active proxy");
-        // A library that doesn't exist is an error; null closes the panel.
-        assert!(app.run("window.swatchLibrary", json!({"library": "nope"})).is_err());
-        app.run("window.swatchLibrary", json!({"library": null})).unwrap();
-        assert!(last_open(&app.ui).is_none());
-    }
-
-    #[test]
-    fn modifier_clicks_select_and_add_to_swatches_adds_the_selection() {
-        let mut app = app();
-        let ctx = context();
-        app.run("window.swatchLibrary", json!({"library": "earth-tones"})).unwrap();
-        click(&mut app, &ctx, "Clay 1", Modifiers::COMMAND, 0.0);
-        click(&mut app, &ctx, "Ochre", Modifiers::NONE, 2.0);
-        assert_eq!(selection(&ctx, "library:swatches:earth-tones"), ["Ochre"], "a folder click selects its group");
-        click(&mut app, &ctx, "Clay 3", Modifiers::COMMAND, 4.0);
-        assert!(app.session.doc().unwrap().doc.swatch("Clay 3").is_none(), "modifier clicks only select");
-        let sel = selection(&ctx, "library:swatches:earth-tones");
-        SwatchLibraries::add(&mut app, "earth-tones", sel);
-        let d = &app.session.doc().unwrap().doc;
-        assert_eq!(d.swatch_groups.iter().find(|g| g.name == "Ochre").map(|g| g.swatches.len()), Some(6));
-        assert!(d.swatches.iter().any(|w| w.name == "Clay 3"));
-        // The selection belongs to its library's panel.
-        app.run("window.swatchLibrary", json!({"library": "brights"})).unwrap();
-        assert!(selection(&ctx, "library:swatches:brights").is_empty());
-    }
-
-    #[test]
-    fn a_plain_click_sets_where_a_shift_click_range_starts() {
-        let mut app = app();
-        let ctx = context();
-        app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
-        let (_, lib) = SwatchLibraries::get(&app, "pastels").unwrap();
-        let order: Vec<String> = SwatchLibraries::rows(&lib, "").iter().map(|r| r.name.to_string()).collect();
-        click(&mut app, &ctx, &order[1], Modifiers::NONE, 0.0);
-        click(&mut app, &ctx, &order[4], Modifiers::SHIFT, 2.0);
-        assert_eq!(selection(&ctx, "library:swatches:pastels"), order[1..=4], "the range starts at the plain click");
-        // A plain click after a Cmd/Ctrl-click moves the anchor from the Cmd/Ctrl-clicked item.
-        click(&mut app, &ctx, &order[8], Modifiers::COMMAND, 4.0);
-        click(&mut app, &ctx, &order[2], Modifiers::NONE, 6.0);
-        click(&mut app, &ctx, &order[3], Modifiers::SHIFT, 8.0);
-        assert_eq!(selection(&ctx, "library:swatches:pastels"), order[2..=3]);
-        let d = &app.session.doc().unwrap().doc;
-        assert!(d.swatch(&order[2]).is_some(), "a plain click still adds the swatch");
-        assert!(d.swatch(&order[3]).is_none(), "a Shift-click only selects");
-    }
-
-    #[test]
-    fn find_filters_list_view_and_arrows_step_through_the_libraries() {
-        let mut app = app();
-        let ctx = context();
-        app.run("window.swatchLibrary", json!({"library": "web-safe-216"})).unwrap();
-        let panel = "library:swatches:web-safe-216";
-        app.run("ui.libraryPanel", json!({"panel": panel, "view": "smallList"})).unwrap();
-        ctx.data_mut(|d| d.insert_temp(egui::Id::unique(key(panel, "find")), "#FF00".to_string()));
-        frame(&mut app, &ctx, vec![], Modifiers::NONE, 0.0);
-        frame(&mut app, &ctx, vec![], Modifiers::NONE, 0.5);
-        assert!(ctx.read_response(tile_id(panel, "#FF0033")).is_some());
-        assert!(ctx.read_response(tile_id(panel, "#00FF00")).is_none());
-        let first = SWATCH_IDS[0];
-        let last = SwatchLibraries::list(&app).pop().unwrap().id;
-        assert_eq!(last, "radial-glows", "gradient libraries come after the swatch libraries");
-        assert_eq!(neighbour::<SwatchLibraries>(&app, first, -1), Some(last), "wraps around");
-        assert_eq!(neighbour::<SwatchLibraries>(&app, "web-safe-216", 1).as_deref(), Some(SWATCH_IDS[1]));
-    }
-
-    const SWATCH_IDS: [&str; 9] = [
-        "web-safe-216",
-        "grays-neutrals",
-        "earth-tones",
-        "skin-tone-ramps",
-        "pastels",
-        "brights",
-        "metallic-gradients",
-        "perceptual-scales",
-        "harmony-sets",
-    ];
-
-    #[test]
-    fn the_window_submenu_lists_every_library() {
-        let app = app();
-        let ids: Vec<Value> = crate::menus::menu_entries(&app)
-            .into_iter()
-            .filter(|e| e.path == ["Window", "Swatch Libraries"] && e.command.as_deref() == Some("window.swatchLibrary"))
-            .map(|e| e.params["library"].clone())
-            .collect();
-        let all = vectorcraft_engine::cmd::swatchlib::libraries(&app.session);
-        let listed = |category: &str| all.iter().filter(|l| l.category == category).map(|l| json!(l.id)).collect::<Vec<_>>();
-        assert_eq!(ids, listed("builtIn"));
-        assert_eq!(ids, SWATCH_IDS.map(|i| json!(i)));
-        let gradients: Vec<Value> = crate::menus::menu_entries(&app)
-            .into_iter()
-            .filter(|e| e.path == ["Window", "Swatch Libraries", "Gradients"])
-            .map(|e| e.params["library"].clone())
-            .collect();
-        assert!(gradients.len() >= 5);
-        assert_eq!(gradients, listed("gradients"));
-        let defaults = crate::menus::menu_entries(&app).into_iter().any(|e| e.command.as_deref() == Some("swatch.resetDefaults"));
-        assert!(defaults, "Default Swatches is listed");
-    }
-
-    #[test]
-    fn save_dialog_writes_user_libraries_that_the_window_menu_lists() {
-        let dir = std::env::temp_dir().join(format!("vc-library-panel-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        let mut app = app();
-        app.session.swatch_libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
-        let user_items = |app: &VectorcraftApp| -> Vec<(String, String)> {
-            crate::menus::menu_entries(app)
-                .into_iter()
-                .filter(|e| e.path == ["Window", "Swatch Libraries", "User Defined"])
-                .map(|e| (e.label, e.command.unwrap_or_default()))
-                .collect()
-        };
-        assert!(user_items(&app).is_empty(), "empty slots are hidden");
-        app.run("ui.saveSwatchLibrary", json!({"names": ["Brights"]})).unwrap();
-        let d = app.ui.dialog.as_mut().expect("Save Swatch Library opens");
-        assert_eq!((d.kind.as_str(), d.bool("user")), (crate::dialogs::save_swatch_library::KIND, true));
-        d.fields.insert("name".into(), json!("Loud"));
-        d.fields.insert("selectedOnly".into(), json!(true));
-        let ctx = context();
-        let input = egui::RawInput { screen_rect: Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0))), ..Default::default() };
-        ctx.run_ui(input, |ui| crate::dialogs::show(&mut app, ui.ctx())).textures_delta.clear();
-        assert!(app.ui.dialog.is_some(), "the dialog draws and stays open");
-        crate::dialogs::confirm(&mut app).unwrap();
-        assert!(app.ui.dialog.is_none());
-        assert_eq!(user_items(&app), [("Loud".to_string(), "window.userSwatchLibrary1".to_string())]);
-        app.run("window.userSwatchLibrary1", json!({})).unwrap();
-        assert_eq!(last_open(&app.ui).map(|p| p.id.as_str()), Some("user/Loud.vcswatches"));
-        let (_, lib) = SwatchLibraries::get(&app, "user/Loud.vcswatches").unwrap();
-        assert_eq!((lib.groups.len(), lib.len()), (1, 5), "only the selected group");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn saving_to_a_file_and_opening_a_palette_file() {
-        let written = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
-        let w = written.clone();
-        let services = crate::Services {
-            pick_save: Some(Box::new(|p: &crate::FilePick| Some(format!("/tmp/{}", p.name)))),
-            write: Some(Box::new(move |p: &str, b: &[u8]| {
-                w.borrow_mut().push((p.to_string(), b.to_vec()));
-                Ok(())
-            })),
-            ..Default::default()
-        };
-        let mut app = VectorcraftApp::new(Session::new(), services);
-        app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
-        app.run("ui.saveSwatchLibrary", json!({})).unwrap();
-        let d = app.ui.dialog.as_mut().unwrap();
-        assert!(!d.bool("user") && !d.bool("__user"), "no user folder: a file");
-        d.fields.insert("format".into(), json!("gpl"));
-        crate::dialogs::confirm(&mut app).unwrap();
-        let (path, bytes) = written.borrow()[0].clone();
-        assert!(path.ends_with(".gpl"), "{path}");
-        let text = String::from_utf8(bytes).unwrap();
-        assert!(
-            text.starts_with(
-                "GIMP Palette
-"
-            ) && text.contains(
-                "	Red
-"
-            ),
-            "{text}"
-        );
-        // Opening a palette file opens it in the library panel.
-        crate::io::open_bytes(&mut app, "Saved.gpl", text.as_bytes(), None).unwrap();
-        let open = last_open(&app.ui).cloned().unwrap();
-        assert!(open.id.starts_with("loaded/"), "{open:?}");
-        assert_eq!(app.session.documents().len(), 1, "not opened as a document");
-        let other = SwatchLibraries::list(&app).into_iter().find(|l| l.id == open.id).unwrap();
-        assert_eq!(other.submenu, Some("Other Libraries"));
-        // Built-in libraries' names are interface labels; a file's is shown as it is.
-        for l in SwatchLibraries::list(&app) {
-            assert_eq!(builtin_library(&l.id), !matches!(l.submenu, Some("User Defined" | "Other Libraries")), "{}", l.id);
-        }
-        assert!(!builtin_library(&open.id) && builtin_library(vectorcraft_engine::cmd::swatchlib::DOCUMENT_SWATCHES));
-    }
-
-    #[test]
-    fn the_save_dialog_writes_swatch_exchange_files() {
-        let written = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
-        let w = written.clone();
-        let services = crate::Services {
-            pick_save: Some(Box::new(|p: &crate::FilePick| Some(format!("/tmp/{}", p.name)))),
-            write: Some(Box::new(move |p: &str, b: &[u8]| {
-                w.borrow_mut().push((p.to_string(), b.to_vec()));
-                Ok(())
-            })),
-            ..Default::default()
-        };
-        let mut app = VectorcraftApp::new(Session::new(), services);
-        app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
-        app.run("ui.saveSwatchLibrary", json!({})).unwrap();
-        let d = app.ui.dialog.as_mut().unwrap();
-        d.fields.insert("format".into(), json!("ase"));
-        d.fields.insert("name".into(), json!("Brand Kit"));
-        let text = crate::tests_labels::painted_text(&mut app, |app, ui| crate::dialogs::show(app, ui.ctx()));
-        assert!(text.contains("Swatch Exchange (.ase)") && text.contains("Swatch exchange files keep solid colors only."), "{text}");
-        crate::dialogs::confirm(&mut app).unwrap();
-        let (path, bytes) = written.borrow()[0].clone();
-        assert_eq!(path, "/tmp/Brand Kit.ase", "the save panel suggests the name");
-        let lib = vectorcraft_color::palette_io::read_bytes(&bytes, "x").unwrap();
-        let solid = app.session.doc().unwrap().doc.swatches_iter().filter(|w| w.paint.color().is_some()).count();
-        assert_eq!(lib.len(), solid, "every solid color of the document");
-        // The web downloads the file under that name.
-        let downloads = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
-        let dl = downloads.clone();
-        let services = crate::Services {
-            download: Some(Box::new(move |name: &str, _: &[u8]| {
-                dl.borrow_mut().push(name.to_string());
-                Ok(())
-            })),
-            ..Default::default()
-        };
-        let mut web = VectorcraftApp::new(Session::new(), services);
-        web.run("file.new", json!({"width": 100, "height": 100})).unwrap();
-        web.run("ui.saveSwatchLibrary", json!({})).unwrap();
-        let d = web.ui.dialog.as_mut().unwrap();
-        d.fields.insert("format".into(), json!("ase"));
-        d.fields.insert("name".into(), json!(" Brand: Kit. "));
-        crate::dialogs::confirm(&mut web).unwrap();
-        assert_eq!(*downloads.borrow(), ["Brand- Kit.ase"], "the name made safe as a file name, as for User Defined");
-    }
-
-    #[test]
-    fn swatch_exchange_files_without_a_path_open_in_the_library_panel() {
-        // A file opened on the web has no path; open_bytes passes its bytes as dataBase64.
-        let mut app = app();
-        crate::io::open_bytes(&mut app, "Brand.ase", &vectorcraft_testkit::ase::sample(), None).unwrap();
-        let open = last_open(&app.ui).cloned().unwrap();
-        assert_eq!(open.id, "loaded/Brand.ase");
-        let (_, lib) = SwatchLibraries::get(&app, &open.id).unwrap();
-        assert_eq!((lib.len(), lib.groups.len()), (4, 1));
-        assert_eq!(app.session.documents().len(), 1, "not opened as a document");
-    }
-
-    fn docking(app: &VectorcraftApp) -> &craft_ui::docking::Layout<String> {
-        app.ui.docking.as_ref().expect("library panels live in the shared layout")
-    }
-
-    fn panel_of(reply: Value) -> String {
-        reply["panel"].as_str().expect("the reply names the panel").to_string()
-    }
-
-    fn groups(app: &VectorcraftApp) -> Vec<Vec<String>> {
-        docking(app).floating.iter().map(crate::panel_docking::window_panels).collect()
-    }
-
-    #[test]
-    fn each_library_opens_in_a_panel_of_its_own() {
-        let mut app = app();
-        // Without the shared layout yet, `window.panel` floats a library panel too.
-        app.run("window.panel", json!({"panel": "library:swatches:earth-tones"})).unwrap();
-        assert!(is_open(&app.ui, "library:swatches:earth-tones"));
-        app.run("window.panel.close", json!({"panel": "library:swatches:earth-tones"})).unwrap();
-        let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
-        let brights = panel_of(app.run("window.swatchLibrary", json!({"library": "Brights"})).unwrap());
-        let styles = panel_of(app.run("window.graphicStyleLibrary", json!({"library": "hand-drawn"})).unwrap());
-        assert_eq!([&pastels, &brights, &styles], ["library:swatches:pastels", "library:swatches:brights", "library:graphicStyles:hand-drawn"]);
-        assert_eq!(groups(&app), [vec![pastels.clone()], vec![brights.clone()], vec![styles.clone()]], "each floats on its own");
-        assert_ne!(docking(&app).floating[0].rect, docking(&app).floating[1].rect, "one beside another");
-        assert_eq!(tab_label(&app, &brights).as_deref(), Some("Brights"));
-        // Opening an open library brings its panel forward.
-        app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
-        assert_eq!(groups(&app).len(), 3);
-        assert_eq!(last_open(&app.ui).map(LibraryPanel::panel), Some(pastels.clone()));
-        // They group, dock and close as any panel, and `window.panel` shows one again.
-        app.run("window.panel.move", json!({"panel": brights, "anchor": pastels})).unwrap();
-        assert!(groups(&app).contains(&vec![pastels.clone(), brights.clone()]), "{:?}", groups(&app));
-        app.run("window.panel.dock", json!({"panel": styles})).unwrap();
-        assert!(craft_ui::docking::Layout { root: docking(&app).root.clone(), floating: vec![] }.contains(&styles));
-        app.run("window.panel.close", json!({"panel": brights})).unwrap();
-        assert!(!is_open(&app.ui, &brights) && is_open(&app.ui, &pastels));
-        app.run("window.panel", json!({"panel": brights})).unwrap();
-        assert!(is_open(&app.ui, &brights));
-        assert!(crate::panel_docking::valid(docking(&app)));
-        // `library: null` closes the panels of its kind.
-        app.run("window.swatchLibrary", json!({"library": null})).unwrap();
-        assert!(!any_open::<SwatchLibraries>(&app.ui) && is_open(&app.ui, &styles));
-        // What isn't a library panel's id.
-        for bad in ["library:nope:x", "library:swatches:", "library:swatches", "Library:swatches:pastels"] {
-            assert!(crate::menus::normalize_panel(bad).is_none(), "{bad}");
-        }
-        assert!(app.run("ui.libraryPanel", json!({"panel": "layers"})).is_err());
-        assert!(app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": true})).is_err(), "closed and not persistent");
-        assert!(app.run("ui.libraryPanel", json!({"panel": styles, "view": "huge"})).is_err());
-    }
-
-    /// A context whose frames report their accessibility tree.
-    fn accessible() -> egui::Context {
-        let ctx = context();
-        ctx.enable_accesskit();
-        ctx
-    }
-
-    /// One frame of `draw` with `events`, after the frames `ctx` ran.
-    fn draw_frame(
-        app: &mut VectorcraftApp,
-        ctx: &egui::Context,
-        draw: &dyn Fn(&mut VectorcraftApp, &mut Ui),
-        events: Vec<Event>,
-    ) -> egui::FullOutput {
-        let screen_rect = Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0)));
-        let time = Some(ctx.input(|i| i.time) + 0.1);
-        let mut out = ctx.run_ui(egui::RawInput { events, time, screen_rect, ..Default::default() }, |ui| draw(app, ui));
-        out.textures_delta.clear();
-        out
-    }
-
-    /// Whether the control `draw` shows that screen readers name `label` is enabled, and its center.
-    fn control(app: &mut VectorcraftApp, ctx: &egui::Context, draw: &dyn Fn(&mut VectorcraftApp, &mut Ui), label: &str) -> (bool, Pos2) {
-        draw_frame(app, ctx, draw, vec![]);
-        let out = draw_frame(app, ctx, draw, vec![]);
-        let nodes = &out.platform_output.accesskit_update.as_ref().expect("an accessibility tree").nodes;
-        let (_, node) = nodes.iter().find(|(_, n)| n.label().map(str::trim) == Some(label)).unwrap_or_else(|| panic!("no control named {label:?}"));
-        let b = node.bounds().expect("bounds");
-        (!node.is_disabled(), Pos2::new((b.x0 + b.x1) as f32 * 0.5, (b.y0 + b.y1) as f32 * 0.5))
-    }
-
-    /// A click at `at` in a frame of `draw`.
-    fn click_at(app: &mut VectorcraftApp, ctx: &egui::Context, draw: &dyn Fn(&mut VectorcraftApp, &mut Ui), at: Pos2) {
-        let button = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers: Modifiers::NONE };
-        draw_frame(app, ctx, draw, vec![Event::PointerMoved(at)]);
-        draw_frame(app, ctx, draw, vec![button(true), button(false)]);
-    }
-
-    /// The app restarted with the preferences `app` saves.
-    fn restarted(app: &VectorcraftApp) -> VectorcraftApp {
-        let saved: crate::UiState = serde_json::from_slice(&serde_json::to_vec(&app.ui).unwrap()).unwrap();
-        let mut next = VectorcraftApp::new(Session::new(), Default::default());
-        next.ui = saved.sanitized();
-        restore(&mut next);
-        next
-    }
-
-    #[test]
-    fn persistent_panels_reopen_at_startup_with_their_settings() {
-        let dir = std::env::temp_dir().join(format!("vc-persistent-libraries-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(&dir).unwrap();
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
-        let mut app = app();
-        let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
-        let brights = panel_of(app.run("window.swatchLibrary", json!({"library": "brights"})).unwrap());
-        let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
-        let r = app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": true, "view": "largeList", "showFind": false})).unwrap();
-        assert_eq!((r["persistent"].as_bool(), r["view"].as_str(), r["showFind"].as_bool()), (Some(true), Some("largeList"), Some(false)));
-        app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
-        app.run("window.panel.float", json!({"panel": pastels, "x": 40, "y": 90})).unwrap();
-        // A persistent panel reopens even when it was closed.
-        app.run("window.panel.close", json!({"panel": brand})).unwrap();
-        let next = restarted(&app);
-        assert!(is_open(&next.ui, &pastels) && is_open(&next.ui, &brand), "{}", next.ui.status);
-        assert!(!is_open(&next.ui, &brights), "a panel that isn't persistent closed with the app");
-        let group = docking(&next).floating.iter().find(|g| g.contains(&pastels)).unwrap();
-        assert_eq!(group.rect[..2], [40.0, 90.0], "where it was");
-        let s = settings(&next.ui, "swatches", "pastels").unwrap();
-        assert_eq!((s.view, s.hide_find, s.persistent), (Some(View::LargeList), true, true));
-        let (_, id) = parse(&brand).unwrap();
-        assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()), "read again from its file");
-        assert!(next.ui.status.is_empty(), "{}", next.ui.status);
-        assert!(next.ui.docking_hidden.keys().all(|p| p != &brights));
-        // Unchecked, a panel no longer reopens; one whose file is gone reopens as missing, with a note.
-        let mut next = next;
-        next.run("ui.libraryPanel", json!({"panel": pastels, "persistent": false})).unwrap();
-        std::fs::remove_file(&gpl).unwrap();
-        let last = restarted(&next);
-        assert!(!is_open(&last.ui, &pastels) && is_open(&last.ui, &brand));
-        assert!(last.ui.status.contains("Brand.gpl"), "{}", last.ui.status);
-        assert_eq!(last.ui.library_panels.iter().map(LibraryPanel::panel).collect::<Vec<_>>(), [brand]);
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn a_persistent_panel_whose_file_is_gone_is_listed_as_missing_until_located() {
-        let dir = std::env::temp_dir().join(format!("vc-missing-library-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(dir.join("moved")).unwrap();
-        let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, palette).unwrap();
-        let mut app = app();
-        let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
-        app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true, "view": "smallList"})).unwrap();
-        std::fs::remove_file(&gpl).unwrap();
-        // The panel reopens showing its library as missing, and the preferences keep it.
-        let mut next = restarted(&app);
-        tidy(&mut next);
-        assert!(is_open(&next.ui, &brand), "{}", next.ui.status);
-        assert!(next.ui.status.contains("Brand.gpl"), "{}", next.ui.status);
-        let (_, gone) = parse(&brand).unwrap();
-        let s = settings(&next.ui, "swatches", gone).cloned().unwrap();
-        assert_eq!((s.path, s.persistent, s.view), (Some(gpl.to_string_lossy().into_owned()), true, Some(View::SmallList)));
-        assert_eq!(tab_label(&next, &brand).as_deref(), Some("Brand"));
-        // Closed, it opens again by its library's id.
-        next.run("window.panel.close", json!({"panel": brand})).unwrap();
-        let r = next.run("window.swatchLibrary", json!({"library": gone})).unwrap();
-        assert_eq!((r["panel"].as_str(), r["name"].as_str(), r["count"].as_u64()), (Some(brand.as_str()), Some("Brand"), Some(0)));
-        assert!(is_open(&next.ui, &brand));
-        let text = crate::tests_labels::painted_text(&mut next, |app, ui| show(app, ui, &brand));
-        let shown = format!("Missing: {}", gpl.to_string_lossy());
-        assert!(text.contains(&shown), "{text}");
-        let ctx = accessible();
-        let body = |app: &mut VectorcraftApp, ui: &mut Ui| show(app, ui, &brand);
-        assert!(!control(&mut next, &ctx, &body, "Locate Library…").0, "dimmed without an open dialog");
-        let panel_menu = |app: &mut VectorcraftApp, ui: &mut Ui| menu(app, ui, &brand);
-        assert!(!control(&mut next, &ctx, &panel_menu, "Next Library").0, "no library to step from");
-        let mut next = restarted(&next);
-        assert!(is_open(&next.ui, &brand), "still listed after another restart");
-        // Locate Library… reads the file where it is now and shows it in the same panel.
-        assert!(next.run("ui.libraryPanel.locate", json!({"panel": "layers"})).is_err());
-        let moved = dir.join("moved").join("Brand.gpl");
-        std::fs::write(&moved, palette).unwrap();
-        let picked = moved.to_string_lossy().into_owned();
-        next.services.pick_open = Some(Box::new(move |_: &crate::FilePick| Some(picked.clone())));
-        let (enabled, at) = control(&mut next, &ctx, &body, "Locate Library…");
-        assert!(enabled);
-        click_at(&mut next, &ctx, &body, at);
-        let located = panel_id("swatches", &format!("loaded/{}", moved.to_string_lossy()));
-        assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &located), "{}", next.ui.status);
-        let (_, id) = parse(&located).unwrap();
-        assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()));
-        let s = settings(&next.ui, "swatches", id).cloned().unwrap();
-        assert_eq!((s.path, s.persistent, s.view), (Some(moved.to_string_lossy().into_owned()), true, Some(View::SmallList)));
-        assert!(settings(&next.ui, "swatches", gone).is_none());
-        let located_menu = |app: &mut VectorcraftApp, ui: &mut Ui| menu(app, ui, &located);
-        assert!(control(&mut next, &ctx, &located_menu, "Next Library").0);
-        let last = restarted(&next);
-        assert!(is_open(&last.ui, &located) && last.ui.status.is_empty(), "{}", last.ui.status);
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn locating_a_library_open_in_its_own_panel_brings_that_panel_forward() {
-        let dir = std::env::temp_dir().join(format!("vc-locate-open-library-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(&dir).unwrap();
-        let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, palette).unwrap();
-        let mut app = app();
-        let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
-        app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
-        std::fs::remove_file(&gpl).unwrap();
-        let mut next = restarted(&app);
-        let copy = dir.join("Copy.gpl");
-        std::fs::write(&copy, palette).unwrap();
-        let other = panel_of(next.run("window.swatchLibrary.other", json!({"path": copy.to_string_lossy()})).unwrap());
-        next.run("window.panel.close", json!({"panel": brand})).unwrap();
-        assert!(next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": copy.to_string_lossy()})).is_err(), "a closed panel");
-        next.run("window.panel", json!({"panel": brand})).unwrap();
-        let r = next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": copy.to_string_lossy()})).unwrap();
-        assert_eq!((r["panel"].as_str(), r["persistent"].as_bool()), (Some(other.as_str()), Some(true)));
-        assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &other));
-        assert!(next.ui.library_panels.iter().all(|p| p.panel() != brand), "the missing panel is forgotten");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn locate_library_leaves_a_panel_whose_library_is_there_alone() {
-        let dir = std::env::temp_dir().join(format!("vc-locate-found-library-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(&dir).unwrap();
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
-        let mut app = app();
-        let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
-        for persistent in [false, true] {
-            app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": persistent})).unwrap();
-            let e = app.run("ui.libraryPanel.locate", json!({"panel": pastels, "path": gpl.to_string_lossy()})).unwrap_err();
-            assert!(e.contains("isn't missing its library"), "{e}");
-            assert!(is_open(&app.ui, &pastels), "persistent: {persistent}");
-            assert_eq!(settings(&app.ui, "swatches", "pastels").map(|s| s.persistent), Some(persistent));
-        }
-        assert!(SwatchLibraries::get(&app, &format!("loaded/{}", gpl.to_string_lossy())).is_none(), "the file isn't loaded");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn locate_library_reads_a_missing_library_whose_panel_is_no_longer_persistent() {
-        let dir = std::env::temp_dir().join(format!("vc-locate-not-persistent-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(dir.join("moved")).unwrap();
-        let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, palette).unwrap();
-        let mut app = app();
-        let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
-        app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
-        std::fs::remove_file(&gpl).unwrap();
-        let mut next = restarted(&app);
-        // After a command turns Persistent off, the panel stays open on its missing library until the next frame's tidy.
-        next.run("ui.libraryPanel", json!({"panel": brand, "persistent": false})).unwrap();
-        assert!(is_open(&next.ui, &brand));
-        let moved = dir.join("moved").join("Brand.gpl");
-        std::fs::write(&moved, palette).unwrap();
-        let r = next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": moved.to_string_lossy()})).unwrap();
-        let located = panel_id("swatches", &format!("loaded/{}", moved.to_string_lossy()));
-        assert_eq!((r["panel"].as_str(), r["persistent"].as_bool()), (Some(located.as_str()), Some(false)));
-        assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &located), "{}", next.ui.status);
-        let (_, id) = parse(&located).unwrap();
-        assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()));
-        tidy(&mut next);
-        assert!(is_open(&next.ui, &located), "its library is there now");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn an_open_panel_whose_library_is_missing_is_brought_forward_by_its_id_when_not_persistent() {
-        let dir = std::env::temp_dir().join(format!("vc-open-not-persistent-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(&dir).unwrap();
-        let gpl = dir.join("Brand.gpl");
-        std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
-        let mut app = app();
-        let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
-        app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
-        std::fs::remove_file(&gpl).unwrap();
-        let mut next = restarted(&app);
-        // After a command turns Persistent off, the panel stays open on its missing library until the next frame's tidy.
-        next.run("ui.libraryPanel", json!({"panel": brand, "persistent": false})).unwrap();
-        let (_, gone) = parse(&brand).unwrap();
-        let r = next.run("window.swatchLibrary", json!({"library": gone})).unwrap();
-        assert_eq!((r["panel"].as_str(), r["name"].as_str(), r["count"].as_u64()), (Some(brand.as_str()), Some("Brand"), Some(0)));
-        assert!(is_open(&next.ui, &brand));
-        tidy(&mut next);
-        assert!(!is_open(&next.ui, &brand), "a panel that isn't persistent still closes");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn previous_and_next_show_the_neighbouring_library_in_the_same_panel() {
-        let mut app = app();
-        let first = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
-        app.run("window.panel.float", json!({"panel": first, "x": 50, "y": 60})).unwrap();
-        app.run("ui.libraryPanel", json!({"panel": first, "persistent": true, "view": "smallList"})).unwrap();
-        step::<SwatchLibraries>(&mut app, "pastels", 1);
-        let next = panel_id("swatches", SWATCH_IDS[5]);
-        assert!(!is_open(&app.ui, &first) && is_open(&app.ui, &next), "{}", app.ui.status);
-        let group = docking(&app).floating.iter().find(|g| g.contains(&next)).unwrap();
-        assert_eq!((group.panels().count(), group.rect[0], group.rect[1]), (1, 50.0, 60.0), "in its place");
-        let s = settings(&app.ui, "swatches", SWATCH_IDS[5]).unwrap();
-        assert_eq!((s.view, s.persistent), (Some(View::SmallList), true), "the panel keeps its settings");
-        assert!(settings(&app.ui, "swatches", "pastels").is_none());
-        assert!(crate::panel_docking::valid(docking(&app)));
-        // A library open in a panel of its own is brought forward instead.
-        app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
-        let r = app.run("ui.libraryPanel", json!({"panel": next, "library": "Pastels"})).unwrap();
-        assert_eq!(r["panel"], json!(first));
-        assert!(is_open(&app.ui, &next) && is_open(&app.ui, &first));
-    }
-
-    #[test]
-    fn a_panel_closes_when_its_library_is_gone() {
-        let dir = std::env::temp_dir().join(format!("vc-gone-library-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        std::fs::create_dir_all(&dir).unwrap();
-        std::fs::write(dir.join("Gone.gpl"), "GIMP Palette\nName: Gone\n#\n0 0 0\tInk\n").unwrap();
-        std::fs::write(dir.join("Kept.gpl"), "GIMP Palette\nName: Kept\n#\n0 0 0\tInk\n").unwrap();
-        let mut app = app();
-        app.session.swatch_libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
-        let panel = panel_of(app.run("window.swatchLibrary", json!({"library": "user/Gone.gpl"})).unwrap());
-        let kept = panel_of(app.run("window.swatchLibrary", json!({"library": "user/Kept.gpl"})).unwrap());
-        app.run("ui.libraryPanel", json!({"panel": kept, "persistent": true})).unwrap();
-        tidy(&mut app);
-        assert!(is_open(&app.ui, &panel));
-        std::fs::remove_file(dir.join("Gone.gpl")).unwrap();
-        std::fs::remove_file(dir.join("Kept.gpl")).unwrap();
-        app.session.swatch_libraries.rescan();
-        tidy(&mut app);
-        assert!(!is_open(&app.ui, &panel));
-        // A persistent panel stays open and shows its library as missing.
-        assert!(is_open(&app.ui, &kept));
-        assert_eq!(tab_label(&app, &kept).as_deref(), Some("Kept"));
-        let text = crate::tests_labels::painted_text(&mut app, |app, ui| show(app, ui, &kept));
-        assert!(text.contains("Missing: user/Kept.gpl"), "{text}");
-        let _ = std::fs::remove_dir_all(dir);
-    }
-
-    #[test]
-    fn the_panel_menu_has_persistent() {
-        let mut app = app();
-        let panel = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
-        let text = crate::tests_labels::painted_text(&mut app, |app, ui| menu(app, ui, &panel));
-        for item in ["Add to Swatches", "Small List View", "Show Find Field", "Previous Library", "Persistent", "Close Library"] {
-            assert!(text.contains(item), "{item}: {text}");
-        }
-    }
-}
+mod tests;
diff --git a/crates/ui-egui/src/panels/library_panel/tests.rs b/crates/ui-egui/src/panels/library_panel/tests.rs
new file mode 100644
index 000000000..ac01d4f44
--- /dev/null
+++ b/crates/ui-egui/src/panels/library_panel/tests.rs
@@ -0,0 +1,656 @@
+use egui::{Event, Modifiers, PointerButton, Pos2, vec2};
+use serde_json::Value;
+use vectorcraft_color::Paint;
+use vectorcraft_engine::Session;
+
+use super::*;
+use crate::panels::swatches::SwatchLibraries;
+
+fn app() -> VectorcraftApp {
+    let mut app = VectorcraftApp::new(Session::new(), Default::default());
+    app.run("file.new", json!({"width": 200, "height": 200})).unwrap();
+    app
+}
+
+fn context() -> egui::Context {
+    let ctx = egui::Context::default();
+    crate::theme::install_fonts(&ctx);
+    ctx
+}
+
+/// One frame of the library panel with `events` and `modifiers` held.
+fn frame(app: &mut VectorcraftApp, ctx: &egui::Context, events: Vec<Event>, modifiers: Modifiers, time: f64) {
+    let screen_rect = Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0)));
+    let events = std::iter::once(Event::ModifiersChanged(modifiers)).chain(events).collect();
+    let input = egui::RawInput { events, time: Some(time), screen_rect, ..Default::default() };
+    let mut out = ctx.run_ui(input, |ui| show_window(app, ui.ctx()));
+    out.textures_delta.clear();
+}
+
+/// The panel opened last.
+fn shown(app: &VectorcraftApp) -> String {
+    last_open(&app.ui).expect("a library panel is open").panel()
+}
+
+/// Click the tile or row of `name` in the panel opened last with `modifiers` (frames from
+/// `time` to `time + 0.5`; a new window takes a sizing frame first).
+fn click(app: &mut VectorcraftApp, ctx: &egui::Context, name: &str, modifiers: Modifiers, time: f64) {
+    frame(app, ctx, vec![], Modifiers::NONE, time);
+    frame(app, ctx, vec![], Modifiers::NONE, time + 0.25);
+    let at = ctx.read_response(tile_id(&shown(app), name)).unwrap_or_else(|| panic!("no tile for {name}")).rect.center();
+    let button = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers };
+    frame(app, ctx, vec![Event::PointerMoved(at), button(true), button(false)], modifiers, time + 0.5);
+}
+
+fn undo_len(app: &VectorcraftApp) -> usize {
+    app.session.doc().unwrap().history.undo.len()
+}
+
+#[test]
+fn clicking_a_library_swatch_adds_and_applies_it_in_one_step() {
+    let mut app = app();
+    let ctx = context();
+    let r = app.run("window.swatchLibrary", json!({"library": "Pastels"})).unwrap();
+    assert_eq!((r["open"].as_str(), r["count"].as_u64(), r["panel"].as_str()), (Some("pastels"), Some(24), Some("library:swatches:pastels")));
+    assert_eq!(last_open(&app.ui).map(|p| (p.kind.as_str(), p.id.as_str())), Some(("swatches", "pastels")));
+    let undo = undo_len(&app);
+    click(&mut app, &ctx, "Pastel Teal", Modifiers::NONE, 0.0);
+    let d = &app.session.doc().unwrap().doc;
+    let added = d.swatch("Pastel Teal").expect("added to the document");
+    assert_eq!(app.session.paint.fill, Paint::solid(added.paint.color().unwrap()), "applied to the fill");
+    assert_eq!(undo_len(&app), undo + 1);
+    // Alt-click paints the stroke (the inactive proxy).
+    click(&mut app, &ctx, "Soft Blue", Modifiers::ALT, 2.0);
+    let blue = app.session.doc().unwrap().doc.swatch("Soft Blue").and_then(|w| w.paint.color()).unwrap();
+    assert_eq!(app.session.paint.stroke.color(), Some(blue));
+    assert!(app.session.fill_active, "Alt keeps the active proxy");
+    // A library that doesn't exist is an error; null closes the panel.
+    assert!(app.run("window.swatchLibrary", json!({"library": "nope"})).is_err());
+    app.run("window.swatchLibrary", json!({"library": null})).unwrap();
+    assert!(last_open(&app.ui).is_none());
+}
+
+#[test]
+fn modifier_clicks_select_and_add_to_swatches_adds_the_selection() {
+    let mut app = app();
+    let ctx = context();
+    app.run("window.swatchLibrary", json!({"library": "earth-tones"})).unwrap();
+    click(&mut app, &ctx, "Clay 1", Modifiers::COMMAND, 0.0);
+    click(&mut app, &ctx, "Ochre", Modifiers::NONE, 2.0);
+    assert_eq!(selection(&ctx, "library:swatches:earth-tones"), ["Ochre"], "a folder click selects its group");
+    click(&mut app, &ctx, "Clay 3", Modifiers::COMMAND, 4.0);
+    assert!(app.session.doc().unwrap().doc.swatch("Clay 3").is_none(), "modifier clicks only select");
+    let sel = selection(&ctx, "library:swatches:earth-tones");
+    SwatchLibraries::add(&mut app, "earth-tones", sel);
+    let d = &app.session.doc().unwrap().doc;
+    assert_eq!(d.swatch_groups.iter().find(|g| g.name == "Ochre").map(|g| g.swatches.len()), Some(6));
+    assert!(d.swatches.iter().any(|w| w.name == "Clay 3"));
+    // The selection belongs to its library's panel.
+    app.run("window.swatchLibrary", json!({"library": "brights"})).unwrap();
+    assert!(selection(&ctx, "library:swatches:brights").is_empty());
+}
+
+#[test]
+fn a_plain_click_sets_where_a_shift_click_range_starts() {
+    let mut app = app();
+    let ctx = context();
+    app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
+    let (_, lib) = SwatchLibraries::get(&app, "pastels").unwrap();
+    let order: Vec<String> = SwatchLibraries::rows(&lib, "").iter().map(|r| r.name.to_string()).collect();
+    click(&mut app, &ctx, &order[1], Modifiers::NONE, 0.0);
+    click(&mut app, &ctx, &order[4], Modifiers::SHIFT, 2.0);
+    assert_eq!(selection(&ctx, "library:swatches:pastels"), order[1..=4], "the range starts at the plain click");
+    // A plain click after a Cmd/Ctrl-click moves the anchor from the Cmd/Ctrl-clicked item.
+    click(&mut app, &ctx, &order[8], Modifiers::COMMAND, 4.0);
+    click(&mut app, &ctx, &order[2], Modifiers::NONE, 6.0);
+    click(&mut app, &ctx, &order[3], Modifiers::SHIFT, 8.0);
+    assert_eq!(selection(&ctx, "library:swatches:pastels"), order[2..=3]);
+    let d = &app.session.doc().unwrap().doc;
+    assert!(d.swatch(&order[2]).is_some(), "a plain click still adds the swatch");
+    assert!(d.swatch(&order[3]).is_none(), "a Shift-click only selects");
+}
+
+#[test]
+fn find_filters_list_view_and_arrows_step_through_the_libraries() {
+    let mut app = app();
+    let ctx = context();
+    app.run("window.swatchLibrary", json!({"library": "web-safe-216"})).unwrap();
+    let panel = "library:swatches:web-safe-216";
+    app.run("ui.libraryPanel", json!({"panel": panel, "view": "smallList"})).unwrap();
+    ctx.data_mut(|d| d.insert_temp(egui::Id::unique(key(panel, "find")), "#FF00".to_string()));
+    frame(&mut app, &ctx, vec![], Modifiers::NONE, 0.0);
+    frame(&mut app, &ctx, vec![], Modifiers::NONE, 0.5);
+    assert!(ctx.read_response(tile_id(panel, "#FF0033")).is_some());
+    assert!(ctx.read_response(tile_id(panel, "#00FF00")).is_none());
+    let first = SWATCH_IDS[0];
+    let last = SwatchLibraries::list(&app).pop().unwrap().id;
+    assert_eq!(last, "radial-glows", "gradient libraries come after the swatch libraries");
+    assert_eq!(neighbour::<SwatchLibraries>(&app, first, -1), Some(last), "wraps around");
+    assert_eq!(neighbour::<SwatchLibraries>(&app, "web-safe-216", 1).as_deref(), Some(SWATCH_IDS[1]));
+}
+
+const SWATCH_IDS: [&str; 9] = [
+    "web-safe-216",
+    "grays-neutrals",
+    "earth-tones",
+    "skin-tone-ramps",
+    "pastels",
+    "brights",
+    "metallic-gradients",
+    "perceptual-scales",
+    "harmony-sets",
+];
+
+#[test]
+fn the_window_submenu_lists_every_library() {
+    let app = app();
+    let ids: Vec<Value> = crate::menus::menu_entries(&app)
+        .into_iter()
+        .filter(|e| e.path == ["Window", "Swatch Libraries"] && e.command.as_deref() == Some("window.swatchLibrary"))
+        .map(|e| e.params["library"].clone())
+        .collect();
+    let all = vectorcraft_engine::cmd::swatchlib::libraries(&app.session);
+    let listed = |category: &str| all.iter().filter(|l| l.category == category).map(|l| json!(l.id)).collect::<Vec<_>>();
+    assert_eq!(ids, listed("builtIn"));
+    assert_eq!(ids, SWATCH_IDS.map(|i| json!(i)));
+    let gradients: Vec<Value> = crate::menus::menu_entries(&app)
+        .into_iter()
+        .filter(|e| e.path == ["Window", "Swatch Libraries", "Gradients"])
+        .map(|e| e.params["library"].clone())
+        .collect();
+    assert!(gradients.len() >= 5);
+    assert_eq!(gradients, listed("gradients"));
+    let defaults = crate::menus::menu_entries(&app).into_iter().any(|e| e.command.as_deref() == Some("swatch.resetDefaults"));
+    assert!(defaults, "Default Swatches is listed");
+}
+
+#[test]
+fn save_dialog_writes_user_libraries_that_the_window_menu_lists() {
+    let dir = std::env::temp_dir().join(format!("vc-library-panel-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    let mut app = app();
+    app.session.swatch_libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
+    let user_items = |app: &VectorcraftApp| -> Vec<(String, String)> {
+        crate::menus::menu_entries(app)
+            .into_iter()
+            .filter(|e| e.path == ["Window", "Swatch Libraries", "User Defined"])
+            .map(|e| (e.label, e.command.unwrap_or_default()))
+            .collect()
+    };
+    assert!(user_items(&app).is_empty(), "empty slots are hidden");
+    app.run("ui.saveSwatchLibrary", json!({"names": ["Brights"]})).unwrap();
+    let d = app.ui.dialog.as_mut().expect("Save Swatch Library opens");
+    assert_eq!((d.kind.as_str(), d.bool("user")), (crate::dialogs::save_swatch_library::KIND, true));
+    d.fields.insert("name".into(), json!("Loud"));
+    d.fields.insert("selectedOnly".into(), json!(true));
+    let ctx = context();
+    let input = egui::RawInput { screen_rect: Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0))), ..Default::default() };
+    ctx.run_ui(input, |ui| crate::dialogs::show(&mut app, ui.ctx())).textures_delta.clear();
+    assert!(app.ui.dialog.is_some(), "the dialog draws and stays open");
+    crate::dialogs::confirm(&mut app).unwrap();
+    assert!(app.ui.dialog.is_none());
+    assert_eq!(user_items(&app), [("Loud".to_string(), "window.userSwatchLibrary1".to_string())]);
+    app.run("window.userSwatchLibrary1", json!({})).unwrap();
+    assert_eq!(last_open(&app.ui).map(|p| p.id.as_str()), Some("user/Loud.vcswatches"));
+    let (_, lib) = SwatchLibraries::get(&app, "user/Loud.vcswatches").unwrap();
+    assert_eq!((lib.groups.len(), lib.len()), (1, 5), "only the selected group");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn saving_to_a_file_and_opening_a_palette_file() {
+    let written = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
+    let w = written.clone();
+    let services = crate::Services {
+        pick_save: Some(Box::new(|p: &crate::FilePick| Some(format!("/tmp/{}", p.name)))),
+        write: Some(Box::new(move |p: &str, b: &[u8]| {
+            w.borrow_mut().push((p.to_string(), b.to_vec()));
+            Ok(())
+        })),
+        ..Default::default()
+    };
+    let mut app = VectorcraftApp::new(Session::new(), services);
+    app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
+    app.run("ui.saveSwatchLibrary", json!({})).unwrap();
+    let d = app.ui.dialog.as_mut().unwrap();
+    assert!(!d.bool("user") && !d.bool("__user"), "no user folder: a file");
+    d.fields.insert("format".into(), json!("gpl"));
+    crate::dialogs::confirm(&mut app).unwrap();
+    let (path, bytes) = written.borrow()[0].clone();
+    assert!(path.ends_with(".gpl"), "{path}");
+    let text = String::from_utf8(bytes).unwrap();
+    assert!(
+        text.starts_with(
+            "GIMP Palette
+"
+        ) && text.contains(
+            "	Red
+"
+        ),
+        "{text}"
+    );
+    // Opening a palette file opens it in the library panel.
+    crate::io::open_bytes(&mut app, "Saved.gpl", text.as_bytes(), None).unwrap();
+    let open = last_open(&app.ui).cloned().unwrap();
+    assert!(open.id.starts_with("loaded/"), "{open:?}");
+    assert_eq!(app.session.documents().len(), 1, "not opened as a document");
+    let other = SwatchLibraries::list(&app).into_iter().find(|l| l.id == open.id).unwrap();
+    assert_eq!(other.submenu, Some("Other Libraries"));
+    // Built-in libraries' names are interface labels; a file's is shown as it is.
+    for l in SwatchLibraries::list(&app) {
+        assert_eq!(builtin_library(&l.id), !matches!(l.submenu, Some("User Defined" | "Other Libraries")), "{}", l.id);
+    }
+    assert!(!builtin_library(&open.id) && builtin_library(vectorcraft_engine::cmd::swatchlib::DOCUMENT_SWATCHES));
+}
+
+#[test]
+fn the_save_dialog_writes_swatch_exchange_files() {
+    let written = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
+    let w = written.clone();
+    let services = crate::Services {
+        pick_save: Some(Box::new(|p: &crate::FilePick| Some(format!("/tmp/{}", p.name)))),
+        write: Some(Box::new(move |p: &str, b: &[u8]| {
+            w.borrow_mut().push((p.to_string(), b.to_vec()));
+            Ok(())
+        })),
+        ..Default::default()
+    };
+    let mut app = VectorcraftApp::new(Session::new(), services);
+    app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
+    app.run("ui.saveSwatchLibrary", json!({})).unwrap();
+    let d = app.ui.dialog.as_mut().unwrap();
+    d.fields.insert("format".into(), json!("ase"));
+    d.fields.insert("name".into(), json!("Brand Kit"));
+    let text = crate::tests_labels::painted_text(&mut app, |app, ui| crate::dialogs::show(app, ui.ctx()));
+    assert!(text.contains("Swatch Exchange (.ase)") && text.contains("Swatch exchange files keep solid colors only."), "{text}");
+    crate::dialogs::confirm(&mut app).unwrap();
+    let (path, bytes) = written.borrow()[0].clone();
+    assert_eq!(path, "/tmp/Brand Kit.ase", "the save panel suggests the name");
+    let lib = vectorcraft_color::palette_io::read_bytes(&bytes, "x").unwrap();
+    let solid = app.session.doc().unwrap().doc.swatches_iter().filter(|w| w.paint.color().is_some()).count();
+    assert_eq!(lib.len(), solid, "every solid color of the document");
+    // The web downloads the file under that name.
+    let downloads = std::rc::Rc::new(std::cell::RefCell::new(vec![]));
+    let dl = downloads.clone();
+    let services = crate::Services {
+        download: Some(Box::new(move |name: &str, _: &[u8]| {
+            dl.borrow_mut().push(name.to_string());
+            Ok(())
+        })),
+        ..Default::default()
+    };
+    let mut web = VectorcraftApp::new(Session::new(), services);
+    web.run("file.new", json!({"width": 100, "height": 100})).unwrap();
+    web.run("ui.saveSwatchLibrary", json!({})).unwrap();
+    let d = web.ui.dialog.as_mut().unwrap();
+    d.fields.insert("format".into(), json!("ase"));
+    d.fields.insert("name".into(), json!(" Brand: Kit. "));
+    crate::dialogs::confirm(&mut web).unwrap();
+    assert_eq!(*downloads.borrow(), ["Brand- Kit.ase"], "the name made safe as a file name, as for User Defined");
+}
+
+#[test]
+fn swatch_exchange_files_without_a_path_open_in_the_library_panel() {
+    // A file opened on the web has no path; open_bytes passes its bytes as dataBase64.
+    let mut app = app();
+    crate::io::open_bytes(&mut app, "Brand.ase", &vectorcraft_testkit::ase::sample(), None).unwrap();
+    let open = last_open(&app.ui).cloned().unwrap();
+    assert_eq!(open.id, "loaded/Brand.ase");
+    let (_, lib) = SwatchLibraries::get(&app, &open.id).unwrap();
+    assert_eq!((lib.len(), lib.groups.len()), (4, 1));
+    assert_eq!(app.session.documents().len(), 1, "not opened as a document");
+}
+
+fn docking(app: &VectorcraftApp) -> &craft_ui::docking::Layout<String> {
+    app.ui.docking.as_ref().expect("library panels live in the shared layout")
+}
+
+fn panel_of(reply: Value) -> String {
+    reply["panel"].as_str().expect("the reply names the panel").to_string()
+}
+
+fn groups(app: &VectorcraftApp) -> Vec<Vec<String>> {
+    docking(app).floating.iter().map(crate::panel_docking::window_panels).collect()
+}
+
+#[test]
+fn each_library_opens_in_a_panel_of_its_own() {
+    let mut app = app();
+    // Without the shared layout yet, `window.panel` floats a library panel too.
+    app.run("window.panel", json!({"panel": "library:swatches:earth-tones"})).unwrap();
+    assert!(is_open(&app.ui, "library:swatches:earth-tones"));
+    app.run("window.panel.close", json!({"panel": "library:swatches:earth-tones"})).unwrap();
+    let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
+    let brights = panel_of(app.run("window.swatchLibrary", json!({"library": "Brights"})).unwrap());
+    let styles = panel_of(app.run("window.graphicStyleLibrary", json!({"library": "hand-drawn"})).unwrap());
+    assert_eq!([&pastels, &brights, &styles], ["library:swatches:pastels", "library:swatches:brights", "library:graphicStyles:hand-drawn"]);
+    assert_eq!(groups(&app), [vec![pastels.clone()], vec![brights.clone()], vec![styles.clone()]], "each floats on its own");
+    assert_ne!(docking(&app).floating[0].rect, docking(&app).floating[1].rect, "one beside another");
+    assert_eq!(tab_label(&app, &brights).as_deref(), Some("Brights"));
+    // Opening an open library brings its panel forward.
+    app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
+    assert_eq!(groups(&app).len(), 3);
+    assert_eq!(last_open(&app.ui).map(LibraryPanel::panel), Some(pastels.clone()));
+    // They group, dock and close as any panel, and `window.panel` shows one again.
+    app.run("window.panel.move", json!({"panel": brights, "anchor": pastels})).unwrap();
+    assert!(groups(&app).contains(&vec![pastels.clone(), brights.clone()]), "{:?}", groups(&app));
+    app.run("window.panel.dock", json!({"panel": styles})).unwrap();
+    assert!(craft_ui::docking::Layout { root: docking(&app).root.clone(), floating: vec![] }.contains(&styles));
+    app.run("window.panel.close", json!({"panel": brights})).unwrap();
+    assert!(!is_open(&app.ui, &brights) && is_open(&app.ui, &pastels));
+    app.run("window.panel", json!({"panel": brights})).unwrap();
+    assert!(is_open(&app.ui, &brights));
+    assert!(crate::panel_docking::valid(docking(&app)));
+    // `library: null` closes the panels of its kind.
+    app.run("window.swatchLibrary", json!({"library": null})).unwrap();
+    assert!(!any_open::<SwatchLibraries>(&app.ui) && is_open(&app.ui, &styles));
+    // What isn't a library panel's id.
+    for bad in ["library:nope:x", "library:swatches:", "library:swatches", "Library:swatches:pastels"] {
+        assert!(crate::menus::normalize_panel(bad).is_none(), "{bad}");
+    }
+    assert!(app.run("ui.libraryPanel", json!({"panel": "layers"})).is_err());
+    assert!(app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": true})).is_err(), "closed and not persistent");
+    assert!(app.run("ui.libraryPanel", json!({"panel": styles, "view": "huge"})).is_err());
+}
+
+/// A context whose frames report their accessibility tree.
+fn accessible() -> egui::Context {
+    let ctx = context();
+    ctx.enable_accesskit();
+    ctx
+}
+
+/// One frame of `draw` with `events`, after the frames `ctx` ran.
+fn draw_frame(
+    app: &mut VectorcraftApp,
+    ctx: &egui::Context,
+    draw: &dyn Fn(&mut VectorcraftApp, &mut Ui),
+    events: Vec<Event>,
+) -> egui::FullOutput {
+    let screen_rect = Some(Rect::from_min_size(Pos2::ZERO, vec2(1200.0, 800.0)));
+    let time = Some(ctx.input(|i| i.time) + 0.1);
+    let mut out = ctx.run_ui(egui::RawInput { events, time, screen_rect, ..Default::default() }, |ui| draw(app, ui));
+    out.textures_delta.clear();
+    out
+}
+
+/// Whether the control `draw` shows that screen readers name `label` is enabled, and its center.
+fn control(app: &mut VectorcraftApp, ctx: &egui::Context, draw: &dyn Fn(&mut VectorcraftApp, &mut Ui), label: &str) -> (bool, Pos2) {
+    draw_frame(app, ctx, draw, vec![]);
+    let out = draw_frame(app, ctx, draw, vec![]);
+    let nodes = &out.platform_output.accesskit_update.as_ref().expect("an accessibility tree").nodes;
+    let (_, node) = nodes.iter().find(|(_, n)| n.label().map(str::trim) == Some(label)).unwrap_or_else(|| panic!("no control named {label:?}"));
+    let b = node.bounds().expect("bounds");
+    (!node.is_disabled(), Pos2::new((b.x0 + b.x1) as f32 * 0.5, (b.y0 + b.y1) as f32 * 0.5))
+}
+
+/// A click at `at` in a frame of `draw`.
+fn click_at(app: &mut VectorcraftApp, ctx: &egui::Context, draw: &dyn Fn(&mut VectorcraftApp, &mut Ui), at: Pos2) {
+    let button = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers: Modifiers::NONE };
+    draw_frame(app, ctx, draw, vec![Event::PointerMoved(at)]);
+    draw_frame(app, ctx, draw, vec![button(true), button(false)]);
+}
+
+/// The app restarted with the preferences `app` saves.
+fn restarted(app: &VectorcraftApp) -> VectorcraftApp {
+    let saved: crate::UiState = serde_json::from_slice(&serde_json::to_vec(&app.ui).unwrap()).unwrap();
+    let mut next = VectorcraftApp::new(Session::new(), Default::default());
+    next.ui = saved.sanitized();
+    restore(&mut next);
+    next
+}
+
+#[test]
+fn persistent_panels_reopen_at_startup_with_their_settings() {
+    let dir = std::env::temp_dir().join(format!("vc-persistent-libraries-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
+    let mut app = app();
+    let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
+    let brights = panel_of(app.run("window.swatchLibrary", json!({"library": "brights"})).unwrap());
+    let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
+    let r = app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": true, "view": "largeList", "showFind": false})).unwrap();
+    assert_eq!((r["persistent"].as_bool(), r["view"].as_str(), r["showFind"].as_bool()), (Some(true), Some("largeList"), Some(false)));
+    app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
+    app.run("window.panel.float", json!({"panel": pastels, "x": 40, "y": 90})).unwrap();
+    // A persistent panel reopens even when it was closed.
+    app.run("window.panel.close", json!({"panel": brand})).unwrap();
+    let next = restarted(&app);
+    assert!(is_open(&next.ui, &pastels) && is_open(&next.ui, &brand), "{}", next.ui.status);
+    assert!(!is_open(&next.ui, &brights), "a panel that isn't persistent closed with the app");
+    let group = docking(&next).floating.iter().find(|g| g.contains(&pastels)).unwrap();
+    assert_eq!(group.rect[..2], [40.0, 90.0], "where it was");
+    let s = settings(&next.ui, "swatches", "pastels").unwrap();
+    assert_eq!((s.view, s.hide_find, s.persistent), (Some(View::LargeList), true, true));
+    let (_, id) = parse(&brand).unwrap();
+    assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()), "read again from its file");
+    assert!(next.ui.status.is_empty(), "{}", next.ui.status);
+    assert!(next.ui.docking_hidden.keys().all(|p| p != &brights));
+    // Unchecked, a panel no longer reopens; one whose file is gone reopens as missing, with a note.
+    let mut next = next;
+    next.run("ui.libraryPanel", json!({"panel": pastels, "persistent": false})).unwrap();
+    std::fs::remove_file(&gpl).unwrap();
+    let last = restarted(&next);
+    assert!(!is_open(&last.ui, &pastels) && is_open(&last.ui, &brand));
+    assert!(last.ui.status.contains("Brand.gpl"), "{}", last.ui.status);
+    assert_eq!(last.ui.library_panels.iter().map(LibraryPanel::panel).collect::<Vec<_>>(), [brand]);
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn a_persistent_panel_whose_file_is_gone_is_listed_as_missing_until_located() {
+    let dir = std::env::temp_dir().join(format!("vc-missing-library-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(dir.join("moved")).unwrap();
+    let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, palette).unwrap();
+    let mut app = app();
+    let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
+    app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true, "view": "smallList"})).unwrap();
+    std::fs::remove_file(&gpl).unwrap();
+    // The panel reopens showing its library as missing, and the preferences keep it.
+    let mut next = restarted(&app);
+    tidy(&mut next);
+    assert!(is_open(&next.ui, &brand), "{}", next.ui.status);
+    assert!(next.ui.status.contains("Brand.gpl"), "{}", next.ui.status);
+    let (_, gone) = parse(&brand).unwrap();
+    let s = settings(&next.ui, "swatches", gone).cloned().unwrap();
+    assert_eq!((s.path, s.persistent, s.view), (Some(gpl.to_string_lossy().into_owned()), true, Some(View::SmallList)));
+    assert_eq!(tab_label(&next, &brand).as_deref(), Some("Brand"));
+    // Closed, it opens again by its library's id.
+    next.run("window.panel.close", json!({"panel": brand})).unwrap();
+    let r = next.run("window.swatchLibrary", json!({"library": gone})).unwrap();
+    assert_eq!((r["panel"].as_str(), r["name"].as_str(), r["count"].as_u64()), (Some(brand.as_str()), Some("Brand"), Some(0)));
+    assert!(is_open(&next.ui, &brand));
+    let text = crate::tests_labels::painted_text(&mut next, |app, ui| show(app, ui, &brand));
+    let shown = format!("Missing: {}", gpl.to_string_lossy());
+    assert!(text.contains(&shown), "{text}");
+    let ctx = accessible();
+    let body = |app: &mut VectorcraftApp, ui: &mut Ui| show(app, ui, &brand);
+    assert!(!control(&mut next, &ctx, &body, "Locate Library…").0, "dimmed without an open dialog");
+    let panel_menu = |app: &mut VectorcraftApp, ui: &mut Ui| menu(app, ui, &brand);
+    assert!(!control(&mut next, &ctx, &panel_menu, "Next Library").0, "no library to step from");
+    let mut next = restarted(&next);
+    assert!(is_open(&next.ui, &brand), "still listed after another restart");
+    // Locate Library… reads the file where it is now and shows it in the same panel.
+    assert!(next.run("ui.libraryPanel.locate", json!({"panel": "layers"})).is_err());
+    let moved = dir.join("moved").join("Brand.gpl");
+    std::fs::write(&moved, palette).unwrap();
+    let picked = moved.to_string_lossy().into_owned();
+    next.services.pick_open = Some(Box::new(move |_: &crate::FilePick| Some(picked.clone())));
+    let (enabled, at) = control(&mut next, &ctx, &body, "Locate Library…");
+    assert!(enabled);
+    click_at(&mut next, &ctx, &body, at);
+    let located = panel_id("swatches", &format!("loaded/{}", moved.to_string_lossy()));
+    assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &located), "{}", next.ui.status);
+    let (_, id) = parse(&located).unwrap();
+    assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()));
+    let s = settings(&next.ui, "swatches", id).cloned().unwrap();
+    assert_eq!((s.path, s.persistent, s.view), (Some(moved.to_string_lossy().into_owned()), true, Some(View::SmallList)));
+    assert!(settings(&next.ui, "swatches", gone).is_none());
+    let located_menu = |app: &mut VectorcraftApp, ui: &mut Ui| menu(app, ui, &located);
+    assert!(control(&mut next, &ctx, &located_menu, "Next Library").0);
+    let last = restarted(&next);
+    assert!(is_open(&last.ui, &located) && last.ui.status.is_empty(), "{}", last.ui.status);
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn locating_a_library_open_in_its_own_panel_brings_that_panel_forward() {
+    let dir = std::env::temp_dir().join(format!("vc-locate-open-library-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, palette).unwrap();
+    let mut app = app();
+    let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
+    app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
+    std::fs::remove_file(&gpl).unwrap();
+    let mut next = restarted(&app);
+    let copy = dir.join("Copy.gpl");
+    std::fs::write(&copy, palette).unwrap();
+    let other = panel_of(next.run("window.swatchLibrary.other", json!({"path": copy.to_string_lossy()})).unwrap());
+    next.run("window.panel.close", json!({"panel": brand})).unwrap();
+    assert!(next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": copy.to_string_lossy()})).is_err(), "a closed panel");
+    next.run("window.panel", json!({"panel": brand})).unwrap();
+    let r = next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": copy.to_string_lossy()})).unwrap();
+    assert_eq!((r["panel"].as_str(), r["persistent"].as_bool()), (Some(other.as_str()), Some(true)));
+    assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &other));
+    assert!(next.ui.library_panels.iter().all(|p| p.panel() != brand), "the missing panel is forgotten");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn locate_library_leaves_a_panel_whose_library_is_there_alone() {
+    let dir = std::env::temp_dir().join(format!("vc-locate-found-library-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
+    let mut app = app();
+    let pastels = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
+    for persistent in [false, true] {
+        app.run("ui.libraryPanel", json!({"panel": pastels, "persistent": persistent})).unwrap();
+        let e = app.run("ui.libraryPanel.locate", json!({"panel": pastels, "path": gpl.to_string_lossy()})).unwrap_err();
+        assert!(e.contains("isn't missing its library"), "{e}");
+        assert!(is_open(&app.ui, &pastels), "persistent: {persistent}");
+        assert_eq!(settings(&app.ui, "swatches", "pastels").map(|s| s.persistent), Some(persistent));
+    }
+    assert!(SwatchLibraries::get(&app, &format!("loaded/{}", gpl.to_string_lossy())).is_none(), "the file isn't loaded");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn locate_library_reads_a_missing_library_whose_panel_is_no_longer_persistent() {
+    let dir = std::env::temp_dir().join(format!("vc-locate-not-persistent-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(dir.join("moved")).unwrap();
+    let palette = "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n";
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, palette).unwrap();
+    let mut app = app();
+    let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
+    app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
+    std::fs::remove_file(&gpl).unwrap();
+    let mut next = restarted(&app);
+    // After a command turns Persistent off, the panel stays open on its missing library until the next frame's tidy.
+    next.run("ui.libraryPanel", json!({"panel": brand, "persistent": false})).unwrap();
+    assert!(is_open(&next.ui, &brand));
+    let moved = dir.join("moved").join("Brand.gpl");
+    std::fs::write(&moved, palette).unwrap();
+    let r = next.run("ui.libraryPanel.locate", json!({"panel": brand, "path": moved.to_string_lossy()})).unwrap();
+    let located = panel_id("swatches", &format!("loaded/{}", moved.to_string_lossy()));
+    assert_eq!((r["panel"].as_str(), r["persistent"].as_bool()), (Some(located.as_str()), Some(false)));
+    assert!(!is_open(&next.ui, &brand) && is_open(&next.ui, &located), "{}", next.ui.status);
+    let (_, id) = parse(&located).unwrap();
+    assert!(SwatchLibraries::get(&next, id).is_some_and(|(_, lib)| lib.swatch("Red").is_some()));
+    tidy(&mut next);
+    assert!(is_open(&next.ui, &located), "its library is there now");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn an_open_panel_whose_library_is_missing_is_brought_forward_by_its_id_when_not_persistent() {
+    let dir = std::env::temp_dir().join(format!("vc-open-not-persistent-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let gpl = dir.join("Brand.gpl");
+    std::fs::write(&gpl, "GIMP Palette\nName: Brand\n#\n255   0   0\tRed\n").unwrap();
+    let mut app = app();
+    let brand = panel_of(app.run("window.swatchLibrary.other", json!({"path": gpl.to_string_lossy()})).unwrap());
+    app.run("ui.libraryPanel", json!({"panel": brand, "persistent": true})).unwrap();
+    std::fs::remove_file(&gpl).unwrap();
+    let mut next = restarted(&app);
+    // After a command turns Persistent off, the panel stays open on its missing library until the next frame's tidy.
+    next.run("ui.libraryPanel", json!({"panel": brand, "persistent": false})).unwrap();
+    let (_, gone) = parse(&brand).unwrap();
+    let r = next.run("window.swatchLibrary", json!({"library": gone})).unwrap();
+    assert_eq!((r["panel"].as_str(), r["name"].as_str(), r["count"].as_u64()), (Some(brand.as_str()), Some("Brand"), Some(0)));
+    assert!(is_open(&next.ui, &brand));
+    tidy(&mut next);
+    assert!(!is_open(&next.ui, &brand), "a panel that isn't persistent still closes");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn previous_and_next_show_the_neighbouring_library_in_the_same_panel() {
+    let mut app = app();
+    let first = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
+    app.run("window.panel.float", json!({"panel": first, "x": 50, "y": 60})).unwrap();
+    app.run("ui.libraryPanel", json!({"panel": first, "persistent": true, "view": "smallList"})).unwrap();
+    step::<SwatchLibraries>(&mut app, "pastels", 1);
+    let next = panel_id("swatches", SWATCH_IDS[5]);
+    assert!(!is_open(&app.ui, &first) && is_open(&app.ui, &next), "{}", app.ui.status);
+    let group = docking(&app).floating.iter().find(|g| g.contains(&next)).unwrap();
+    assert_eq!((group.panels().count(), group.rect[0], group.rect[1]), (1, 50.0, 60.0), "in its place");
+    let s = settings(&app.ui, "swatches", SWATCH_IDS[5]).unwrap();
+    assert_eq!((s.view, s.persistent), (Some(View::SmallList), true), "the panel keeps its settings");
+    assert!(settings(&app.ui, "swatches", "pastels").is_none());
+    assert!(crate::panel_docking::valid(docking(&app)));
+    // A library open in a panel of its own is brought forward instead.
+    app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap();
+    let r = app.run("ui.libraryPanel", json!({"panel": next, "library": "Pastels"})).unwrap();
+    assert_eq!(r["panel"], json!(first));
+    assert!(is_open(&app.ui, &next) && is_open(&app.ui, &first));
+}
+
+#[test]
+fn a_panel_closes_when_its_library_is_gone() {
+    let dir = std::env::temp_dir().join(format!("vc-gone-library-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    std::fs::write(dir.join("Gone.gpl"), "GIMP Palette\nName: Gone\n#\n0 0 0\tInk\n").unwrap();
+    std::fs::write(dir.join("Kept.gpl"), "GIMP Palette\nName: Kept\n#\n0 0 0\tInk\n").unwrap();
+    let mut app = app();
+    app.session.swatch_libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
+    let panel = panel_of(app.run("window.swatchLibrary", json!({"library": "user/Gone.gpl"})).unwrap());
+    let kept = panel_of(app.run("window.swatchLibrary", json!({"library": "user/Kept.gpl"})).unwrap());
+    app.run("ui.libraryPanel", json!({"panel": kept, "persistent": true})).unwrap();
+    tidy(&mut app);
+    assert!(is_open(&app.ui, &panel));
+    std::fs::remove_file(dir.join("Gone.gpl")).unwrap();
+    std::fs::remove_file(dir.join("Kept.gpl")).unwrap();
+    app.session.swatch_libraries.rescan();
+    tidy(&mut app);
+    assert!(!is_open(&app.ui, &panel));
+    // A persistent panel stays open and shows its library as missing.
+    assert!(is_open(&app.ui, &kept));
+    assert_eq!(tab_label(&app, &kept).as_deref(), Some("Kept"));
+    let text = crate::tests_labels::painted_text(&mut app, |app, ui| show(app, ui, &kept));
+    assert!(text.contains("Missing: user/Kept.gpl"), "{text}");
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn the_panel_menu_has_persistent() {
+    let mut app = app();
+    let panel = panel_of(app.run("window.swatchLibrary", json!({"library": "pastels"})).unwrap());
+    let text = crate::tests_labels::painted_text(&mut app, |app, ui| menu(app, ui, &panel));
+    for item in ["Add to Swatches", "Small List View", "Show Find Field", "Previous Library", "Persistent", "Close Library"] {
+        assert!(text.contains(item), "{item}: {text}");
+    }
+}