Merge pull request #1702 from MarcelP102/Pallet-placement

[UX] Pallets you can dock, group and float (including LAYERS panel)

assets/icons/ui/pin_active.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#000000" stroke-width="1.9" stroke-linecap="round" stroke-linejoin="round"><g transform="rotate(30 12 12)"><path d="M8 3 H16 L15 9 L18 12 V14 H6 V12 L9 9 Z"/><path d="M12 14 V21"/></g></svg>

assets/icons/ui/resize_left.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#B4B6B9" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><path d="M3 9 L15 21 M3 15 L9 21 M3 21 L4 21"/></svg>

locales/ar-SA/opencadstudio.ftl

@@ -6176,3 +6176,12 @@ count-feature =
     .invalid-boundary = كائن حد منطقة العد غير صالح. حدد خطًا متعددًا مغلقًا يتكون من قطع مستقيمة ولا يتقاطع مع نفسه.
     .block-not-found = تعذر العثور على الكتلة "__ocs_fmt_0__".
     .invalid-point = نقطة غير صالحة.
+
+dock =
+    .allow-docking = السماح بالإرساء
+    .auto-hide = إخفاء تلقائي
+    .dock-left = إرساء إلى اليسار
+    .dock-right = إرساء إلى اليمين
+    .new-group = مجموعة جديدة
+    .browser = المستعرض
+    .node-graph = مخطط العقد

locales/bg-BG/opencadstudio.ftl

@@ -6164,3 +6164,12 @@ count-feature =
     .invalid-boundary = Невалиден обект за граница на областта за преброяване. Изберете затворена полилиния от отсечки, която не се самопресича.
     .block-not-found = Блокът "__ocs_fmt_0__" не може да бъде намерен.
     .invalid-point = Невалидна точка.
+
+dock =
+    .allow-docking = Разреши закачане
+    .auto-hide = Автоматично скриване
+    .dock-left = Закачи вляво
+    .dock-right = Закачи вдясно
+    .new-group = Нова група
+    .browser = Браузър
+    .node-graph = Граф на възлите

locales/cs-CZ/opencadstudio.ftl

@@ -6161,3 +6161,12 @@ count-feature =
     .invalid-boundary = Neplatný objekt hranice oblasti počítání. Vyberte uzavřenou křivku složenou z úseček, která neprotíná sama sebe.
     .block-not-found = Blok "__ocs_fmt_0__" nelze najít.
     .invalid-point = Neplatný bod.
+
+dock =
+    .allow-docking = Povolit ukotvení
+    .auto-hide = Automaticky skrýt
+    .dock-left = Ukotvit vlevo
+    .dock-right = Ukotvit vpravo
+    .new-group = Nová skupina
+    .browser = Prohlížeč
+    .node-graph = Graf uzlů

locales/de-DE/opencadstudio.ftl

@@ -6162,3 +6162,12 @@ count-feature =
     .invalid-boundary = Ungültiges Begrenzungsobjekt für den Zählbereich. Wählen Sie eine geschlossene Polylinie aus Liniensegmenten, die sich nicht selbst schneidet.
     .block-not-found = Block "__ocs_fmt_0__" wurde nicht gefunden.
     .invalid-point = Ungültiger Punkt.
+
+dock =
+    .allow-docking = Andocken zulassen
+    .auto-hide = Automatisch ausblenden
+    .dock-left = Links andocken
+    .dock-right = Rechts andocken
+    .new-group = Neue Gruppe
+    .browser = Browser
+    .node-graph = Knotengraph

locales/el-GR/opencadstudio.ftl

@@ -6164,3 +6164,12 @@ count-feature =
     .invalid-boundary = Μη έγκυρο αντικείμενο ορίου περιοχής καταμέτρησης. Επιλέξτε μια κλειστή πολυγραμμή από ευθύγραμμα τμήματα που δεν τέμνει τον εαυτό της.
     .block-not-found = Το μπλοκ "__ocs_fmt_0__" δεν βρέθηκε.
     .invalid-point = Μη έγκυρο σημείο.
+
+dock =
+    .allow-docking = Να επιτρέπεται η πρόσδεση
+    .auto-hide = Αυτόματη απόκρυψη
+    .dock-left = Πρόσδεση αριστερά
+    .dock-right = Πρόσδεση δεξιά
+    .new-group = Νέα ομάδα
+    .browser = Περιηγητής
+    .node-graph = Γράφος κόμβων

locales/en-US/opencadstudio.ftl

@@ -6165,3 +6165,12 @@ count-feature =
     .invalid-boundary = Invalid count area boundary object. Select a closed polyline consisting of line segments and does not intersect itself.
     .block-not-found = Block "__ocs_fmt_0__" cannot be found.
     .invalid-point = Invalid point.
+
+dock =
+    .allow-docking = Allow docking
+    .auto-hide = Auto-hide
+    .dock-left = Dock left
+    .dock-right = Dock right
+    .new-group = New group
+    .browser = Browser
+    .node-graph = Node Graph

locales/es-ES/opencadstudio.ftl

@@ -6164,3 +6164,12 @@ count-feature =
     .invalid-boundary = Objeto de contorno de área de recuento no válido. Seleccione una polilínea cerrada formada por segmentos de línea que no se corte a sí misma.
     .block-not-found = No se encuentra el bloque "__ocs_fmt_0__".
     .invalid-point = Punto no válido.
+
+dock =
+    .allow-docking = Permitir acoplar
+    .auto-hide = Ocultar automáticamente
+    .dock-left = Acoplar a la izquierda
+    .dock-right = Acoplar a la derecha
+    .new-group = Nuevo grupo
+    .browser = Explorador
+    .node-graph = Grafo de nodos

locales/fi-FI/opencadstudio.ftl

@@ -6161,3 +6161,12 @@ count-feature =
     .invalid-boundary = Virheellinen laskenta-alueen rajaobjekti. Valitse suljettu, janoista koostuva moniviiva, joka ei leikkaa itseään.
     .block-not-found = Lohkoa "__ocs_fmt_0__" ei löydy.
     .invalid-point = Virheellinen piste.
+
+dock =
+    .allow-docking = Salli telakointi
+    .auto-hide = Piilota automaattisesti
+    .dock-left = Telakoi vasemmalle
+    .dock-right = Telakoi oikealle
+    .new-group = Uusi ryhmä
+    .browser = Selain
+    .node-graph = Solmukaavio

locales/fr-FR/opencadstudio.ftl

@@ -6163,3 +6163,12 @@ count-feature =
     .invalid-boundary = Objet de contour de zone de comptage non valide. Sélectionnez une polyligne fermée composée de segments de ligne et qui ne se recoupe pas.
     .block-not-found = Le bloc "__ocs_fmt_0__" est introuvable.
     .invalid-point = Point non valide.
+
+dock =
+    .allow-docking = Autoriser l'ancrage
+    .auto-hide = Masquage automatique
+    .dock-left = Ancrer à gauche
+    .dock-right = Ancrer à droite
+    .new-group = Nouveau groupe
+    .browser = Navigateur
+    .node-graph = Graphe de nœuds

locales/hi-IN/opencadstudio.ftl

@@ -6152,3 +6152,12 @@ count-feature =
     .invalid-boundary = अमान्य गणना क्षेत्र सीमा ऑब्जेक्ट। रेखा खंडों से बनी ऐसी बंद पॉलीलाइन चुनें जो स्वयं को प्रतिच्छेद न करे।
     .block-not-found = ब्लॉक "__ocs_fmt_0__" नहीं मिला।
     .invalid-point = अमान्य बिंदु।
+
+dock =
+    .allow-docking = डॉकिंग की अनुमति दें
+    .auto-hide = स्वतः छिपाएँ
+    .dock-left = बाएँ डॉक करें
+    .dock-right = दाएँ डॉक करें
+    .new-group = नया समूह
+    .browser = ब्राउज़र
+    .node-graph = नोड ग्राफ़

locales/hu-HU/opencadstudio.ftl

@@ -6150,3 +6150,12 @@ count-feature =
     .invalid-boundary = Érvénytelen számlálási kontúrobjektum. Válasszon szakaszokból álló, zárt, önmagát nem metsző vonalláncot.
     .block-not-found = A(z) "__ocs_fmt_0__" blokk nem található.
     .invalid-point = Érvénytelen pont.
+
+dock =
+    .allow-docking = Dokkolás engedélyezése
+    .auto-hide = Automatikus elrejtés
+    .dock-left = Dokkolás balra
+    .dock-right = Dokkolás jobbra
+    .new-group = Új csoport
+    .browser = Böngésző
+    .node-graph = Csomópontgráf

locales/it-IT/opencadstudio.ftl

@@ -6163,3 +6163,12 @@ count-feature =
     .invalid-boundary = Oggetto di contorno dell'area di conteggio non valido. Selezionare una polilinea chiusa composta da segmenti di linea che non si interseca.
     .block-not-found = Impossibile trovare il blocco "__ocs_fmt_0__".
     .invalid-point = Punto non valido.
+
+dock =
+    .allow-docking = Consenti ancoraggio
+    .auto-hide = Nascondi automaticamente
+    .dock-left = Ancora a sinistra
+    .dock-right = Ancora a destra
+    .new-group = Nuovo gruppo
+    .browser = Browser
+    .node-graph = Grafo dei nodi

locales/ja-JP/opencadstudio.ftl

@@ -6152,3 +6152,12 @@ count-feature =
     .invalid-boundary = カウント領域の境界オブジェクトが無効です。線分で構成され、自己交差しない閉じたポリラインを選択してください。
     .block-not-found = ブロック "__ocs_fmt_0__" が見つかりません。
     .invalid-point = 点が無効です。
+
+dock =
+    .allow-docking = ドッキングを許可
+    .auto-hide = 自動的に隠す
+    .dock-left = 左にドッキング
+    .dock-right = 右にドッキング
+    .new-group = 新しいグループ
+    .browser = ブラウザー
+    .node-graph = ノードグラフ

locales/ko-KR/opencadstudio.ftl

@@ -6163,3 +6163,12 @@ count-feature =
     .invalid-boundary = 개수 영역 경계 객체가 잘못되었습니다. 선분으로 구성되고 자체 교차하지 않는 닫힌 폴리선을 선택하십시오.
     .block-not-found = 블록 "__ocs_fmt_0__"을(를) 찾을 수 없습니다.
     .invalid-point = 점이 잘못되었습니다.
+
+dock =
+    .allow-docking = 도킹 허용
+    .auto-hide = 자동 숨기기
+    .dock-left = 왼쪽에 도킹
+    .dock-right = 오른쪽에 도킹
+    .new-group = 새 그룹
+    .browser = 브라우저
+    .node-graph = 노드 그래프

locales/lo-LA/opencadstudio.ftl

@@ -6165,3 +6165,12 @@ count-feature =
     .invalid-boundary = ວັດຖຸຂອບເຂດພື້ນທີ່ການນັບບໍ່ຖືກຕ້ອງ. ກະລຸນາເລືອກເສັ້ນ polyline ແບບປິດທີ່ປະກອບດ້ວຍສ່ວນເສັ້ນຊື່ ແລະ ບໍ່ຕັດກັນເອງ.
     .block-not-found = ບໍ່ພົບເຫັນບລັອກ "__ocs_fmt_0__".
     .invalid-point = ຈຸດບໍ່ຖືກຕ້ອງ.
+
+dock =
+    .allow-docking = ອະນຸຍາດການຕິດຂອບ
+    .auto-hide = ເຊື່ອງອັດຕະໂນມັດ
+    .dock-left = ຕິດຂອບຊ້າຍ
+    .dock-right = ຕິດຂອບຂວາ
+    .new-group = ກຸ່ມໃໝ່
+    .browser = ບຣາວເຊີ
+    .node-graph = ກຣາຟໂນດ

locales/nl-NL/opencadstudio.ftl

@@ -6162,3 +6162,12 @@ count-feature =
     .invalid-boundary = Ongeldig grensobject voor het telgebied. Selecteer een gesloten polylijn die uit lijnsegmenten bestaat en zichzelf niet snijdt.
     .block-not-found = Blok "__ocs_fmt_0__" kan niet worden gevonden.
     .invalid-point = Ongeldig punt.
+
+dock =
+    .allow-docking = Koppelen toestaan
+    .auto-hide = Automatisch verbergen
+    .dock-left = Links koppelen
+    .dock-right = Rechts koppelen
+    .new-group = Nieuwe groep
+    .browser = Browser
+    .node-graph = Knooppuntgrafiek

locales/pl-PL/opencadstudio.ftl

@@ -6163,3 +6163,12 @@ count-feature =
     .invalid-boundary = Nieprawidłowy obiekt obwiedni obszaru liczenia. Wybierz zamkniętą polilinię złożoną z odcinków, która nie przecina samej siebie.
     .block-not-found = Nie można znaleźć bloku "__ocs_fmt_0__".
     .invalid-point = Nieprawidłowy punkt.
+
+dock =
+    .allow-docking = Zezwalaj na dokowanie
+    .auto-hide = Autoukrywanie
+    .dock-left = Zadokuj po lewej
+    .dock-right = Zadokuj po prawej
+    .new-group = Nowa grupa
+    .browser = Przeglądarka
+    .node-graph = Graf węzłów

locales/pt-BR/opencadstudio.ftl

@@ -6164,3 +6164,12 @@ count-feature =
     .invalid-boundary = Objeto de contorno da área de contagem inválido. Selecione uma polilinha fechada composta de segmentos de linha e que não se cruze.
     .block-not-found = O bloco "__ocs_fmt_0__" não foi encontrado.
     .invalid-point = Ponto inválido.
+
+dock =
+    .allow-docking = Permitir encaixe
+    .auto-hide = Ocultar automaticamente
+    .dock-left = Encaixar à esquerda
+    .dock-right = Encaixar à direita
+    .new-group = Novo grupo
+    .browser = Navegador
+    .node-graph = Grafo de nós

locales/ru-RU/opencadstudio.ftl

@@ -6165,3 +6165,12 @@ count-feature =
     .invalid-boundary = Недопустимый объект границы области подсчёта. Выберите замкнутую полилинию из отрезков, которая не пересекает саму себя.
     .block-not-found = Блок "__ocs_fmt_0__" не найден.
     .invalid-point = Недопустимая точка.
+
+dock =
+    .allow-docking = Разрешить закрепление
+    .auto-hide = Автоскрытие
+    .dock-left = Закрепить слева
+    .dock-right = Закрепить справа
+    .new-group = Новая группа
+    .browser = Обозреватель
+    .node-graph = Граф узлов

locales/tr-TR/opencadstudio.ftl

@@ -6087,3 +6087,12 @@ count-feature =
     .invalid-boundary = Geçersiz sayım alanı sınır nesnesi. Doğru parçalarından oluşan, kendisiyle kesişmeyen kapalı bir çoklu çizgi seçin.
     .block-not-found = "__ocs_fmt_0__" bloğu bulunamadı.
     .invalid-point = Geçersiz nokta.
+
+dock =
+    .allow-docking = Yerleştirmeye izin ver
+    .auto-hide = Otomatik gizle
+    .dock-left = Sola yerleştir
+    .dock-right = Sağa yerleştir
+    .new-group = Yeni grup
+    .browser = Tarayıcı
+    .node-graph = Düğüm Grafiği

locales/zh-CN/opencadstudio.ftl

@@ -6147,3 +6147,12 @@ count-feature =
     .invalid-boundary = 无效的计数区域边界对象。请选择由直线段组成且不自交的闭合多段线。
     .block-not-found = 找不到块 "__ocs_fmt_0__"。
     .invalid-point = 无效的点。
+
+dock =
+    .allow-docking = 允许停靠
+    .auto-hide = 自动隐藏
+    .dock-left = 停靠到左侧
+    .dock-right = 停靠到右侧
+    .new-group = 新建组
+    .browser = 浏览器
+    .node-graph = 节点图

locales/zh-TW/opencadstudio.ftl

@@ -6159,3 +6159,12 @@ count-feature =
     .invalid-boundary = 無效的計數區域邊界物件。請選取由線段組成且不自我相交的封閉聚合線。
     .block-not-found = 找不到圖塊 "__ocs_fmt_0__"。
     .invalid-point = 無效的點。
+
+dock =
+    .allow-docking = 允許停駐
+    .auto-hide = 自動隱藏
+    .dock-left = 停駐到左側
+    .dock-right = 停駐到右側
+    .new-group = 新增群組
+    .browser = 瀏覽器
+    .node-graph = 節點圖

src/app/commands/blocks.rs

@@ -929,18 +929,7 @@ impl OpenCADStudio {
                 if self.show_external_references {
                     // Always open expanded so the panel is immediately usable;
                     // dock it on the right if the user closed it from the layout.
-                    if self
+                    self.dock_open_at_default(crate::ui::dock::PanelId::ExternalReferences);
-                        .dock
-                        .location(crate::ui::dock::PanelId::ExternalReferences)
-                        .is_none()
-                    {
-                        self.dock.dock(
-                            crate::ui::dock::PanelId::ExternalReferences,
-                            crate::app::config::DockSide::Right,
-                            usize::MAX,
-                        );
-                    }
-                    self.dock_expanded = Some(crate::ui::dock::PanelId::ExternalReferences);
                     self.refresh_xref_manager();
                 }
             }
@@ -1784,7 +1773,7 @@ mod tests {
         let _ = app.run_command_line("BLOCKPALETTE");
         assert!(app.show_block_palette);
         assert!(
-            app.dock_expanded == Some(crate::ui::dock::PanelId::BlockPalette),
+            app.dock_peek == Some(crate::ui::dock::PanelId::BlockPalette),
             "palette must open expanded, not as the collapsed bar"
         );
         // BLOCKSPALETTE only opens; BLOCKSPALETTECLOSE closes.

src/app/commands/count.rs

@@ -259,13 +259,9 @@ impl OpenCADStudio {
         self.count_palette.show = open;
         self.ribbon.set_count_palette(open);
         if open {
-            if self.dock.location(id).is_none() {
+            self.dock_open_at_default(id);
-                self.dock
+        } else {
-                    .dock(id, crate::app::config::DockSide::Right, usize::MAX);
+            self.dock_unpeek(id);
-            }
-            self.dock_expanded = Some(id);
-        } else if self.dock_expanded == Some(id) {
-            self.dock_expanded = None;
         }
     }
 

src/app/commands/fileops.rs

@@ -384,7 +384,9 @@ impl OpenCADStudio {
             "ORTHO" => return Some(Task::done(Message::ToggleOrtho)),
             "PARALLEL" => return Some(Task::done(Message::SetProjection(true))),
             "PERSP" => return Some(Task::done(Message::SetProjection(false))),
-            "LAYERS" => return Some(Task::done(Message::ToggleLayers)),
+            // LAYERS opens the Layer Manager pallet (its close button or
+            // the toggle message close it).
+            "LAYERS" => self.open_layers_pallet(),
 
             // SCRIPT <path> — run a command script: each non-comment
             // line is fed through the same command path the `--script` startup

src/app/commands/layerprops.rs

@@ -704,15 +704,7 @@ impl OpenCADStudio {
                     // rearrange themselves on upgrade for a panel they have
                     // not asked for.
                     let id = crate::ui::dock::PanelId::Browser;
-                    if self.dock.location(id).is_none() {
+                    self.dock_open_at_default(id);
-                        // dock() clamps an out-of-range index to the end of
-                        // the edge, so this appends below whatever is there.
-                        self.dock
-                            .dock(id, crate::app::config::DockSide::Right, usize::MAX);
-                    }
-                    // Open expanded so it is usable straight away; the pin
-                    // button still collapses it.
-                    self.dock_expanded = Some(id);
                     self.command_line
                         .push_output(crate::t!("Browser opened.").as_ref());
                 } else {

src/app/commands/pdf_underlay.rs

@@ -444,17 +444,11 @@ impl OpenCADStudio {
             "POINTCLOUDMANAGER" => {
                 let id = crate::ui::dock::PanelId::PointCloudManager;
                 self.pc_manager.show = true;
-                if self.dock.location(id).is_none() {
+                self.dock_open_at_default(id);
-                    self.dock
-                        .dock(id, crate::app::config::DockSide::Right, usize::MAX);
-                }
-                self.dock_expanded = Some(id);
             }
             "POINTCLOUDMANAGERCLOSE" => {
                 self.pc_manager.show = false;
-                if self.dock_expanded == Some(crate::ui::dock::PanelId::PointCloudManager) {
+                self.dock_unpeek(crate::ui::dock::PanelId::PointCloudManager);
-                    self.dock_expanded = None;
-                }
             }
             "_PCUNCROP" => self
                 .edit_selected_point_clouds(i, "POINTCLOUDUNCROP", |data| data.croppings.clear()),

src/app/commands/sheet_set.rs

@@ -660,13 +660,9 @@ impl OpenCADStudio {
         self.sheet_set.show = on;
         self.ribbon.set_sheet_set(on);
         if on {
-            if self.dock.location(id).is_none() {
+            self.dock_open_at_default(id);
-                self.dock
+        } else {
-                    .dock(id, crate::app::config::DockSide::Right, usize::MAX);
+            self.dock_unpeek(id);
-            }
-            self.dock_expanded = Some(id);
-        } else if self.dock_expanded == Some(id) {
-            self.dock_expanded = None;
         }
     }
 

src/app/dock/mod.rs

@@ -0,0 +1,12 @@
+//! The app side of docking: pallets docked on the drawing view's edges (one
+//! group shown per edge, listed in an icon strip) or floating over it.
+//!
+//! The persisted layout and its pure geometry live in [`crate::ui::dock`];
+//! this module holds the transient state handling (`update`) and drawing
+//! (`view`).
+
+mod update;
+mod view;
+
+#[cfg(test)]
+mod tests;

src/app/dock/tests.rs

@@ -0,0 +1,670 @@
+//! Dock behaviour through the app: drags, hover, menus, and the real view.
+
+use crate::app::{Message, OpenCADStudio};
+
+fn fresh() -> OpenCADStudio {
+    let mut app = OpenCADStudio::new_for_test();
+    app.automation_op(r#"{"op":"new"}"#);
+    app
+}
+
+#[test]
+fn blockpalette_pin_toggles_autocollapse_and_close_hides() {
+    let mut app = fresh();
+    app.show_block_palette = true;
+    let id = crate::ui::dock::PanelId::BlockPalette;
+    let _ = app.on_dock(crate::ui::dock::DockMsg::AutoCollapseToggle(id));
+    assert!(app.dock.auto_hides(id), "pin enables auto-hide");
+    let _ = app.on_dock(crate::ui::dock::DockMsg::AutoCollapseToggle(id));
+    assert!(!app.dock.auto_hides(id), "second pin disables auto-hide");
+    let _ = app.on_dock(crate::ui::dock::DockMsg::Close(id));
+    assert!(!app.show_block_palette, "close dismisses the sidebar");
+}
+
+/// A hermetic app with a 1600×900 workspace and the default dock layout
+/// (Properties left, block palette right), both shown.
+fn dock_app() -> OpenCADStudio {
+    let mut app = fresh();
+    // Tests load the user's persisted config; reset the dock to a known
+    // state so this stays hermetic.
+    app.dock = Default::default();
+    app.dock.ensure_settings();
+    app.show_properties = true;
+    app.show_block_palette = true;
+    let i = app.active_tab;
+    app.tabs[i].scene.selection.borrow_mut().view.vp_size = (1600.0, 900.0);
+    app.win_size = (1600.0, 900.0).into();
+    app
+}
+
+/// Where the current dock drag would land, if it has started.
+fn drag_target(app: &OpenCADStudio) -> Option<crate::ui::dock::DropTarget> {
+    app.dock_drag
+        .and_then(|d| d.movement())
+        .and_then(|(_, _, target)| target)
+}
+
+/// Press `id`'s title bar at `from`, drag to `to`, and return the target
+/// shown just before release.
+fn drag_panel(
+    app: &mut OpenCADStudio,
+    id: crate::ui::dock::PanelId,
+    from: iced::Point,
+    to: iced::Point,
+) -> Option<crate::ui::dock::DropTarget> {
+    use crate::ui::dock::DockMsg;
+    let _ = app.on_dock(DockMsg::DockGrab(id));
+    let _ = app.on_dock(DockMsg::DragMove(from));
+    let _ = app.on_dock(DockMsg::DragMove(to));
+    let target = drag_target(app);
+    let _ = app.on_dock(DockMsg::DragRelease);
+    target
+}
+
+#[test]
+fn dropping_on_a_pallets_top_or_bottom_half_stacks_above_or_below_it() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DropTarget, PanelId};
+    let mut app = dock_app();
+    let id = PanelId::BlockPalette;
+    assert_eq!(app.dock.location(id), Some((DockSide::Right, 0)));
+    let target = drag_panel(
+        &mut app,
+        id,
+        iced::Point::new(1500.0, 10.0),
+        iced::Point::new(150.0, 300.0),
+    );
+    assert_eq!(
+        target,
+        Some(DropTarget::Join {
+            side: DockSide::Left,
+            group: 0,
+            index: 0
+        })
+    );
+    assert_eq!(
+        app.dock.left[0].panels,
+        vec![PanelId::BlockPalette, PanelId::Properties]
+    );
+    assert!(app.dock.right.is_empty());
+    // The bottom half of a pallet stacks below it.
+    let target = drag_panel(
+        &mut app,
+        id,
+        iced::Point::new(150.0, 100.0),
+        iced::Point::new(150.0, 800.0),
+    );
+    assert_eq!(
+        target,
+        Some(DropTarget::Join {
+            side: DockSide::Left,
+            group: 0,
+            index: 2
+        })
+    );
+    assert_eq!(
+        app.dock.left[0].panels,
+        vec![PanelId::Properties, PanelId::BlockPalette]
+    );
+}
+
+#[test]
+fn dock_dragging_a_lone_pallet_over_its_own_group_is_a_no_op() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DropTarget, PanelId};
+    let mut app = dock_app();
+    let before = app.dock.clone();
+    // The right edge's only group holds just the block palette; drag it
+    // around over itself.
+    let target = drag_panel(
+        &mut app,
+        PanelId::BlockPalette,
+        iced::Point::new(1500.0, 10.0),
+        iced::Point::new(1450.0, 600.0),
+    );
+    assert_eq!(
+        target,
+        Some(DropTarget::Join {
+            side: DockSide::Right,
+            group: 0,
+            index: 1
+        })
+    );
+    assert_eq!(app.dock, before);
+}
+
+#[test]
+fn dock_click_without_drag_changes_nothing() {
+    let mut app = dock_app();
+    let before = app.dock.clone();
+    let id = crate::ui::dock::PanelId::BlockPalette;
+    let p = iced::Point::new(1500.0, 10.0);
+    let target = drag_panel(&mut app, id, p, iced::Point::new(1502.0, 11.0));
+    assert_eq!(target, None, "movement under the threshold is a click");
+    assert_eq!(app.dock, before);
+}
+
+#[test]
+fn dock_drop_below_the_strip_groups_starts_a_new_shown_group() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DropTarget, PanelId};
+    let mut app = dock_app();
+    let (_, plus_top) = app.dock_strip_layout(DockSide::Left);
+    let target = drag_panel(
+        &mut app,
+        PanelId::BlockPalette,
+        iced::Point::new(1500.0, 10.0),
+        iced::Point::new(18.0, plus_top + 10.0),
+    );
+    assert_eq!(
+        target,
+        Some(DropTarget::Edge {
+            side: DockSide::Left,
+            index: 1
+        })
+    );
+    assert_eq!(app.dock.left.len(), 2);
+    assert_eq!(app.dock.left[1].panels, vec![PanelId::BlockPalette]);
+    // The new group is the one shown: the column holds only the palette.
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(1));
+    assert_eq!(app.dock_slot_spans(DockSide::Left), vec![(0, 0.0, 900.0)]);
+}
+
+#[test]
+fn dock_icon_press_switches_the_shown_group() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, PanelId};
+    let mut app = dock_app();
+    app.show_browser = true;
+    app.dock.left = vec![
+        DockGroup::stack(vec![PanelId::Properties, PanelId::BlockPalette]),
+        DockGroup::single(PanelId::Browser),
+    ];
+    app.dock.right.clear();
+    // Group 0 shows both stacked pallets.
+    assert_eq!(app.dock_slot_spans(DockSide::Left).len(), 2);
+    let _ = app.on_dock(DockMsg::IconPress(PanelId::Browser));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(1));
+    assert_eq!(app.dock_slot_spans(DockSide::Left), vec![(0, 0.0, 900.0)]);
+    // Each group keeps its own width.
+    app.dock.set_group_width(DockSide::Left, 1, 400.0);
+    assert_eq!(app.dock_column_width(DockSide::Left), 400.0);
+    let _ = app.on_dock(DockMsg::IconPress(PanelId::BlockPalette));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    assert_eq!(app.dock_column_width(DockSide::Left), 260.0);
+}
+
+#[test]
+fn dock_drop_over_the_viewport_floats_the_panel() {
+    use crate::ui::dock::{DropTarget, PanelId};
+    let mut app = dock_app();
+    let target = drag_panel(
+        &mut app,
+        PanelId::BlockPalette,
+        iced::Point::new(1500.0, 10.0),
+        iced::Point::new(800.0, 400.0),
+    );
+    assert!(matches!(target, Some(DropTarget::Float { .. })));
+    assert!(app.dock.right.is_empty());
+    let f = app
+        .dock
+        .float_rect(PanelId::BlockPalette)
+        .expect("floating");
+    assert!(f.x > 600.0 && f.x < 800.0 && f.y > 350.0 && f.y < 400.0);
+    // Dragging a floating panel keeps the grab point under the pointer.
+    let target = drag_panel(
+        &mut app,
+        PanelId::BlockPalette,
+        iced::Point::new(f.x + 20.0, f.y + 10.0),
+        iced::Point::new(f.x + 120.0, f.y + 60.0),
+    );
+    assert_eq!(
+        target,
+        Some(DropTarget::Float {
+            x: f.x + 100.0,
+            y: f.y + 50.0
+        })
+    );
+    // Opening a floating panel must not re-dock it.
+    assert!(app.dock.is_placed(PanelId::BlockPalette));
+}
+
+#[test]
+fn dock_dragging_an_icon_into_another_group_lands_between_its_icons() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, DropTarget, PanelId, STRIP_CELL_H};
+    let mut app = dock_app();
+    app.show_browser = true;
+    app.dock.left = vec![
+        DockGroup::stack(vec![PanelId::Properties, PanelId::Browser]),
+        DockGroup::single(PanelId::BlockPalette),
+    ];
+    app.dock.right.clear();
+    let (layout, _) = app.dock_strip_layout(DockSide::Left);
+    // Drag the Blocks icon (group 1) to between Properties and Browser.
+    let _ = app.on_dock(DockMsg::IconPress(PanelId::BlockPalette));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(
+        20.0,
+        layout[1].icons_top + 10.0,
+    )));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(
+        20.0,
+        layout[0].icons_top + STRIP_CELL_H + 2.0,
+    )));
+    assert_eq!(
+        drag_target(&app),
+        Some(DropTarget::Join {
+            side: DockSide::Left,
+            group: 0,
+            index: 1
+        })
+    );
+    let _ = app.on_dock(DockMsg::DragRelease);
+    assert_eq!(app.dock.left.len(), 1, "the emptied group goes away");
+    assert_eq!(
+        app.dock.left[0].panels,
+        vec![PanelId::Properties, PanelId::BlockPalette, PanelId::Browser]
+    );
+}
+
+#[test]
+fn dock_grip_drag_moves_a_whole_group() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, PanelId};
+    let mut app = dock_app();
+    app.show_browser = true;
+    app.dock.left = vec![
+        DockGroup::stack(vec![PanelId::Properties, PanelId::Browser]),
+        DockGroup::single(PanelId::BlockPalette),
+    ];
+    app.dock.right.clear();
+    let (layout, plus_top) = app.dock_strip_layout(DockSide::Left);
+    let _ = app.on_dock(DockMsg::GroupGrab(DockSide::Left, 0));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(
+        18.0,
+        layout[0].top + 2.0,
+    )));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(18.0, plus_top + 10.0)));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    assert_eq!(app.dock.left[0].panels, vec![PanelId::BlockPalette]);
+    assert_eq!(
+        app.dock.left[1].panels,
+        vec![PanelId::Properties, PanelId::Browser]
+    );
+    // A group dropped over the viewport does not float or split up.
+    let before = app.dock.clone();
+    let _ = app.on_dock(DockMsg::GroupGrab(DockSide::Left, 1));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(18.0, 300.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(800.0, 400.0)));
+    assert_eq!(drag_target(&app), None);
+    let _ = app.on_dock(DockMsg::DragRelease);
+    assert_eq!(app.dock, before);
+}
+
+#[test]
+fn dock_closed_pallets_take_no_room_and_empty_groups_hide() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, PanelId};
+    let mut app = dock_app();
+    app.dock.left = vec![
+        DockGroup::stack(vec![PanelId::BlockPalette, PanelId::Properties]),
+        DockGroup::single(PanelId::Browser),
+    ];
+    app.show_block_palette = false;
+    app.show_browser = false;
+    // Only Properties is open: one listed group, full height.
+    assert_eq!(app.dock_visible_groups(DockSide::Left), vec![0]);
+    assert_eq!(app.dock_slot_spans(DockSide::Left), vec![(1, 0.0, 900.0)]);
+    // A shown group with nothing open falls back to one that has.
+    app.dock.show_group(DockSide::Left, 1);
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(0));
+}
+
+#[test]
+fn dock_splitter_drag_changes_pallet_heights() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, PanelId};
+    let mut app = dock_app();
+    app.dock.left = vec![DockGroup::stack(vec![
+        PanelId::BlockPalette,
+        PanelId::Properties,
+    ])];
+    app.dock.right.clear();
+    let _ = app.on_dock(DockMsg::SplitGrab(DockSide::Left, 0, 0, 1));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(100.0, 450.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(100.0, 675.0)));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    // 225 px of a 900 px edge holding 2 weight units = 0.5 units.
+    let w = &app.dock.left[0].weights;
+    assert!((w[0] - 1.5).abs() < 1e-4 && (w[1] - 0.5).abs() < 1e-4);
+    let _ = app.on_dock(DockMsg::SplitReset(DockSide::Left, 0));
+    assert_eq!(app.dock.left[0].weights, vec![1.0, 1.0]);
+}
+
+#[test]
+fn dock_hover_reveals_groups_only_on_an_auto_hiding_edge() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, PanelId};
+    let mut app = dock_app();
+    app.show_browser = true;
+    app.dock.left.push(DockGroup::single(PanelId::Browser));
+    // The pin on any docked pallet turns auto-hide on for its edge.
+    let _ = app.on_dock(DockMsg::AutoCollapseToggle(PanelId::Properties));
+    assert!(app.dock.edge_auto_hide(DockSide::Left));
+    assert!(!app.dock.edge_auto_hide(DockSide::Right));
+    assert!(!app.dock_edge_expanded(DockSide::Left));
+    // Hovering an icon flies its group out.
+    let _ = app.on_dock(DockMsg::Hover(PanelId::Browser));
+    // ...but only once the pointer rests: the reveal waits for the delay.
+    assert!(!app.dock_edge_expanded(DockSide::Left));
+    let _ = app.on_dock(DockMsg::HoverSettled(app.dock_hover_gen));
+    assert!(app.dock_edge_expanded(DockSide::Left));
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(1));
+    // Leaving and coming back within the delay keeps it open.
+    let _ = app.on_dock(DockMsg::HoverExit);
+    let stale = app.dock_hover_gen;
+    let _ = app.on_dock(DockMsg::HoverStay);
+    let _ = app.on_dock(DockMsg::HoverSettled(stale));
+    assert!(app.dock_edge_expanded(DockSide::Left));
+    let _ = app.on_dock(DockMsg::HoverExit);
+    let _ = app.on_dock(DockMsg::HoverSettled(app.dock_hover_gen));
+    assert!(!app.dock_edge_expanded(DockSide::Left));
+    // Without auto-hide, hovering does not switch groups (clicks do).
+    let _ = app.on_dock(DockMsg::AutoCollapseToggle(PanelId::Properties));
+    let _ = app.on_dock(DockMsg::Hover(PanelId::Properties));
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(1));
+    assert!(app.dock_edge_expanded(DockSide::Left));
+}
+
+#[test]
+fn dock_float_resize_grows_the_panel() {
+    use crate::ui::dock::{DockMsg, FloatPanel, PanelId};
+    let mut app = dock_app();
+    app.dock.float(FloatPanel::new(
+        PanelId::BlockPalette,
+        100.0,
+        100.0,
+        260.0,
+        300.0,
+    ));
+    let _ = app.on_dock(DockMsg::FloatResizeGrab(PanelId::BlockPalette, false));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(360.0, 400.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(400.0, 450.0)));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    let f = app.dock.float_rect(PanelId::BlockPalette).unwrap();
+    assert_eq!((f.w, f.h), (300.0, 350.0));
+    // The bottom-left grip grows the panel leftward, keeping its right edge.
+    let _ = app.on_dock(DockMsg::FloatResizeGrab(PanelId::BlockPalette, true));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(100.0, 450.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(60.0, 450.0)));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    let g = app.dock.float_rect(PanelId::BlockPalette).unwrap();
+    assert_eq!((g.x, g.w, g.h), (f.x - 40.0, 340.0, 350.0));
+}
+
+#[test]
+fn dock_edge_menu_adds_and_hides_pallets() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockMsg, PanelId};
+    let mut app = dock_app();
+    app.show_browser = false;
+    let _ = app.on_dock(DockMsg::EdgeMenu(Some(DockSide::Left)));
+    // Checking a closed pallet opens it as a new, shown group here.
+    let _ = app.on_dock(DockMsg::EdgeMenuToggle(DockSide::Left, PanelId::Browser));
+    assert!(app.show_browser);
+    assert_eq!(app.dock.left.len(), 2);
+    assert_eq!(app.dock.left[1].panels, vec![PanelId::Browser]);
+    assert_eq!(app.dock_shown_group(DockSide::Left), Some(1));
+    assert_eq!(app.dock_edge_menu, None, "the menu closes after adding");
+    let _ = app.on_dock(DockMsg::EdgeMenu(Some(DockSide::Left)));
+    // Unchecking hides it but keeps its place.
+    let _ = app.on_dock(DockMsg::EdgeMenuToggle(DockSide::Left, PanelId::Browser));
+    assert!(!app.show_browser);
+    assert_eq!(
+        app.dock.location(PanelId::Browser),
+        Some((DockSide::Left, 1))
+    );
+    // Opening it again from the same edge reuses that place.
+    let _ = app.on_dock(DockMsg::EdgeMenuToggle(DockSide::Left, PanelId::Browser));
+    assert_eq!(app.dock.left.len(), 2);
+    // A pallet open on the other edge is not checked here: picking it
+    // moves it over instead of hiding it.
+    let _ = app.on_dock(DockMsg::EdgeMenuToggle(
+        DockSide::Left,
+        PanelId::BlockPalette,
+    ));
+    assert!(app.show_block_palette);
+    assert!(app.dock.right.is_empty());
+    assert_eq!(
+        app.dock.location(PanelId::BlockPalette),
+        Some((DockSide::Left, 2))
+    );
+}
+
+#[test]
+fn dock_divider_resizes_only_its_group() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockGroup, DockMsg, PanelId};
+    let mut app = dock_app();
+    app.dock.left = vec![
+        DockGroup::stack(vec![PanelId::Properties, PanelId::BlockPalette]),
+        DockGroup::single(PanelId::Count),
+    ];
+    app.dock.right.clear();
+    let _ = app.on_dock(DockMsg::ResizeGrab(PanelId::Properties));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(300.0, 100.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(330.0, 100.0)));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    // The group was 260 wide (its widest pallet); it is now 290, while
+    // the other group and the pallets' own widths are untouched.
+    assert_eq!(app.dock_group_width(DockSide::Left, 0), 290.0);
+    assert_eq!(app.dock_group_width(DockSide::Left, 1), 280.0);
+    assert_eq!(app.dock.settings(PanelId::Properties).width, 250.0);
+}
+
+#[test]
+fn layers_command_opens_a_floating_pallet_and_toggles_it_closed() {
+    use crate::ui::dock::PanelId;
+    let mut app = dock_app();
+    let _ = app.update(Message::ToggleLayers);
+    assert!(app.show_layers);
+    assert!(app.active_modal.is_none(), "no modal backdrop");
+    let f = app
+        .dock
+        .float_rect(PanelId::Layers)
+        .expect("floats on first use");
+    assert!(f.x > 0.0 && f.y >= 0.0);
+    let _ = app.update(Message::ToggleLayers);
+    assert!(!app.show_layers);
+    // Its place is kept for next time.
+    assert!(app.dock.float_rect(PanelId::Layers).is_some());
+}
+
+/// A headless renderer for driving the real view.
+fn headless_renderer() -> iced::Renderer {
+    iced_test::futures::futures::executor::block_on(
+        <iced::Renderer as iced_test::core::renderer::Headless>::new(
+            iced_test::core::renderer::Settings::default(),
+            None,
+        ),
+    )
+    .expect("headless renderer")
+}
+
+/// Size the real view is laid out at.
+const VIEW_SIZE: iced::Size = iced::Size::new(1600.0, 900.0);
+
+/// Centre of the first text `label` in the real view.
+fn find_in_view(app: &OpenCADStudio, label: &str) -> iced::Point {
+    use iced_test::core::widget;
+    use iced_test::runtime::user_interface::{Cache, UserInterface};
+    use iced_test::Selector;
+    let mut renderer = headless_renderer();
+    let mut ui = UserInterface::build(app.view_main(), VIEW_SIZE, Cache::default(), &mut renderer);
+    let mut find = Selector::find(label);
+    ui.operate(&renderer, &mut widget::operation::black_box(&mut find));
+    match widget::Operation::finish(&find) {
+        widget::operation::Outcome::Some(Some(target)) => {
+            target.visible_bounds().expect("visible").center()
+        }
+        _ => panic!("{label} not found"),
+    }
+}
+
+/// Drive the real view through iced's `UserInterface` with the pointer at
+/// `at`: feed `events` one at a time, and between events hand the
+/// published messages to the app and rebuild the view while keeping the
+/// widget-tree cache, as the runtime does.
+fn drive_view(app: &mut OpenCADStudio, at: iced::Point, events: &[iced::Event]) {
+    use iced_test::core::{mouse, shell, window};
+    use iced_test::runtime::user_interface::{Cache, UserInterface};
+    let mut renderer = headless_renderer();
+    let mut cache = Cache::default();
+    let cursor = mouse::Cursor::Available(at);
+    for event in events {
+        let mut messages = Vec::new();
+        {
+            let mut ui = UserInterface::build(app.view_main(), VIEW_SIZE, cache, &mut renderer);
+            let _ = ui.update(
+                &window::Headless,
+                &shell::Waker::noop(),
+                std::slice::from_ref(event),
+                cursor,
+                &mut renderer,
+                &mut messages,
+            );
+            cache = ui.into_cache();
+        }
+        for message in messages {
+            let _ = app.update(message);
+        }
+    }
+}
+
+#[test]
+fn docked_title_bar_double_click_floats_the_pallet_in_the_real_view() {
+    use crate::ui::dock::PanelId;
+    let mut app = dock_app();
+    let press = iced::Event::Mouse(iced::mouse::Event::ButtonPressed(iced::mouse::Button::Left));
+    let release = iced::Event::Mouse(iced::mouse::Event::ButtonReleased(
+        iced::mouse::Button::Left,
+    ));
+    // The block palette's title text sits in its docked title bar.
+    let title = find_in_view(&app, "Blocks");
+    drive_view(
+        &mut app,
+        title,
+        &[press.clone(), release.clone(), press, release],
+    );
+    assert!(
+        app.dock.float_rect(PanelId::BlockPalette).is_some(),
+        "a double-click on a docked title bar floats the pallet"
+    );
+}
+
+#[test]
+fn hovering_a_strip_icon_reveals_an_auto_hiding_edge_in_the_real_view() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockMsg, PanelId, STRIP_CELL_H, STRIP_PAD};
+    let mut app = dock_app();
+    // Mirror the layout onto the left so the block palette's title marks
+    // where the workspace starts, then auto-hide the right edge.
+    let title = find_in_view(&app, "Blocks");
+    let _ = app.on_dock(DockMsg::AutoCollapseToggle(PanelId::BlockPalette));
+    assert!(!app.dock_edge_expanded(DockSide::Right));
+    // The title bar text sits ~13 px below the workspace top; the strip's
+    // first icon is centred STRIP_PAD + half a cell below it.
+    let workspace_top = title.y - 13.0;
+    let icon = iced::Point::new(
+        VIEW_SIZE.width - crate::ui::dock::DOCK_STRIP_W / 2.0,
+        workspace_top + STRIP_PAD + STRIP_CELL_H / 2.0,
+    );
+    drive_view(
+        &mut app,
+        icon,
+        &[iced::Event::Mouse(iced::mouse::Event::CursorMoved {
+            position: icon,
+        })],
+    );
+    let _ = app.on_dock(DockMsg::HoverSettled(app.dock_hover_gen));
+    assert!(
+        app.dock_edge_expanded(DockSide::Right),
+        "hovering the icon reveals the auto-hiding edge"
+    );
+}
+
+#[test]
+fn layers_ribbon_button_opens_the_pallet_without_staying_highlighted() {
+    let mut app = dock_app();
+    // The ribbon's LAYERS button runs the LAYERS command.
+    let click = || Message::RibbonToolClick {
+        tool_id: "LAYERS".to_string(),
+        event: crate::modules::ModuleEvent::Command("LAYERS".to_string()),
+    };
+    let _ = app.update(click());
+    assert!(app.show_layers);
+    assert_eq!(app.ribbon.active_tool(), None);
+    // Pressing it again keeps it open, like the Blocks palette's button.
+    let _ = app.update(click());
+    assert!(app.show_layers);
+}
+
+#[test]
+fn dock_double_clicks_float_and_dock_panels() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockMsg, PanelId};
+    let mut app = dock_app();
+    let _ = app.on_dock(DockMsg::FloatOut(PanelId::Properties));
+    assert!(app.dock.left.is_empty());
+    let f = app.dock.float_rect(PanelId::Properties).expect("floating");
+    assert!(f.x > 0.0, "floats clear of the left edge");
+    let _ = app.on_dock(DockMsg::DockTo(PanelId::Properties, DockSide::Right));
+    assert!(app.dock.floating.is_empty());
+    assert_eq!(
+        app.dock.location(PanelId::Properties),
+        Some((DockSide::Right, 1))
+    );
+}
+
+#[test]
+fn blockpalette_width_reset() {
+    use crate::app::config::DockSide;
+    let mut app = dock_app();
+    let id = crate::ui::dock::PanelId::BlockPalette;
+    app.dock.set_group_width(DockSide::Right, 0, 500.0);
+    let _ = app.on_dock(crate::ui::dock::DockMsg::WidthReset(id));
+    assert_eq!(app.dock.group_width(DockSide::Right, 0), 260.0);
+}
+
+#[test]
+fn floating_menu_docks_and_allow_docking_keeps_a_drag_floating() {
+    use crate::app::config::DockSide;
+    use crate::ui::dock::{DockMsg, DropTarget, PanelId};
+    let mut app = dock_app();
+    let _ = app.on_dock(DockMsg::FloatOut(PanelId::BlockPalette));
+    // With Allow docking off, a drag onto the left edge's strip stays
+    // floating.
+    let _ = app.on_dock(DockMsg::FloatMenu(Some(PanelId::BlockPalette)));
+    let _ = app.on_dock(DockMsg::FloatDockingToggle(PanelId::BlockPalette));
+    assert_eq!(app.dock_float_menu, None);
+    assert!(!app.dock.float_rect(PanelId::BlockPalette).unwrap().docking);
+    let _ = app.on_dock(DockMsg::DockGrab(PanelId::BlockPalette));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(500.0, 300.0)));
+    let _ = app.on_dock(DockMsg::DragMove(iced::Point::new(10.0, 60.0)));
+    assert!(matches!(drag_target(&app), Some(DropTarget::Float { .. })));
+    let _ = app.on_dock(DockMsg::DragRelease);
+    let f = app
+        .dock
+        .float_rect(PanelId::BlockPalette)
+        .expect("still floating");
+    assert!(!f.docking, "moving it keeps the choice");
+    // The menu's Dock left still docks it.
+    let _ = app.on_dock(DockMsg::FloatMenu(Some(PanelId::BlockPalette)));
+    let _ = app.on_dock(DockMsg::DockTo(PanelId::BlockPalette, DockSide::Left));
+    assert_eq!(app.dock_float_menu, None);
+    assert_eq!(
+        app.dock.location(PanelId::BlockPalette).map(|(s, _)| s),
+        Some(DockSide::Left)
+    );
+}

src/app/dock/update.rs

@@ -0,0 +1,788 @@
+//! Dock state changes: drags, hover, open / close, and the queries the view
+//! and drop targeting share.
+
+use crate::app::{Message, OpenCADStudio};
+
+/// Pointer travel (px) before pressing a title bar or icon becomes a drag,
+/// so a plain click never moves anything.
+const DOCK_DRAG_THRESHOLD: f32 = 5.0;
+
+/// Resolves once the dock hover delay has passed (a sleeping helper thread;
+/// the web build has none and resolves at once).
+fn hover_delay() -> impl std::future::Future<Output = ()> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let rx = {
+        let (tx, rx) = iced::futures::channel::oneshot::channel::<()>();
+        std::thread::spawn(move || {
+            std::thread::sleep(crate::ui::dock::DOCK_HOVER_DELAY);
+            let _ = tx.send(());
+        });
+        rx
+    };
+    async move {
+        #[cfg(not(target_arch = "wasm32"))]
+        let _ = rx.await;
+    }
+}
+
+impl OpenCADStudio {
+    /// Dock chrome interaction (grab / pin / resize / hover / move) applied to
+    /// whichever panel the message names.
+    pub(crate) fn on_dock(&mut self, m: crate::ui::dock::DockMsg) -> iced::Task<Message> {
+        use crate::app::config::DockSide;
+        use crate::ui::dock::{DockDrag, DockMsg, FloatPanel};
+        match m {
+            DockMsg::DockGrab(id) => self.dock_begin(DockDrag::moving(id, None), Some(id)),
+            DockMsg::IconPress(id) => {
+                // An icon press shows the icon's group and may also start
+                // dragging the pallet; a plain click never passes the drag
+                // threshold.
+                if self.dock.show_group_of(id) {
+                    self.save_config();
+                }
+                self.dock_begin(DockDrag::moving(id, None), Some(id));
+            }
+            DockMsg::GroupGrab(side, gi) => {
+                if let Some(&id) = self.dock_group_visible(side, gi).first() {
+                    self.dock_begin(DockDrag::moving(id, Some((side, gi))), Some(id));
+                }
+            }
+            DockMsg::ResizeGrab(id) => self.dock_begin(DockDrag::Width(id), Some(id)),
+            DockMsg::SplitGrab(side, group, upper, lower) => self.dock_begin(
+                DockDrag::Split {
+                    side,
+                    group,
+                    upper,
+                    lower,
+                },
+                None,
+            ),
+            DockMsg::FloatResizeGrab(panel, from_left) => {
+                self.dock.raise_float(panel);
+                self.dock_begin(DockDrag::FloatSize { panel, from_left }, None);
+            }
+            DockMsg::SplitReset(side, gi) => {
+                self.dock.reset_splits(side, gi);
+                self.save_config();
+            }
+            DockMsg::WidthReset(id) => {
+                // Only docked pallets have the divider that sends this.
+                if let Some((side, gi)) = self.dock.location(id) {
+                    self.dock.reset_group_width(side, gi);
+                    self.save_config();
+                }
+            }
+            DockMsg::TitleHover(id) => self.dock_title_hover = Some(id),
+            DockMsg::TitleHoverEnd(id) => {
+                if self.dock_title_hover == Some(id) {
+                    self.dock_title_hover = None;
+                }
+            }
+            DockMsg::GripHover(side, gi) => self.dock_grip_hover = Some((side, gi)),
+            DockMsg::GripHoverEnd(side, gi) => {
+                if self.dock_grip_hover == Some((side, gi)) {
+                    self.dock_grip_hover = None;
+                }
+            }
+            DockMsg::FloatRaise(id) => self.dock.raise_float(id),
+            DockMsg::FloatOut(id) => {
+                // Float beside the edge it was docked on, near the top.
+                let (ww, _) = self.dock_workspace_size();
+                let (w, h) = self.dock_float_size(id);
+                let strip = crate::ui::dock::DOCK_STRIP_W;
+                let x = match self.dock.location(id) {
+                    Some((DockSide::Right, _)) => {
+                        ww - strip - self.dock_column_width(DockSide::Right) - w - 60.0
+                    }
+                    _ => strip + self.dock_column_width(DockSide::Left) + 40.0,
+                };
+                self.dock_drag = None;
+                if self.dock.float(FloatPanel::new(id, x.max(0.0), 40.0, w, h)) {
+                    self.save_config();
+                }
+            }
+            DockMsg::DockTo(id, side) => {
+                self.dock_drag = None;
+                self.dock_float_menu = None;
+                if self.dock.dock(id, side, usize::MAX) {
+                    self.save_config();
+                }
+            }
+            DockMsg::FloatMenu(id) => {
+                self.dock_float_menu = id;
+                self.dock_float_menu_at = self.dock_float_pointer;
+                if let Some(id) = id {
+                    self.dock.raise_float(id);
+                }
+            }
+            DockMsg::FloatBarPointer(p) => self.dock_float_pointer = p,
+            DockMsg::FloatDockingToggle(id) => {
+                self.dock_float_menu = None;
+                if self.dock.toggle_float_docking(id) {
+                    self.save_config();
+                }
+            }
+            DockMsg::EdgeMenu(side) => self.dock_edge_menu = side,
+            DockMsg::EdgeMenuToggle(side, id) => {
+                // Checked = open and docked on this edge: unchecking hides it.
+                // Anything else (closed, floating, on the other edge) moves
+                // here and opens, in its own group here if it has one, else
+                // as a new group; adding a pallet ends the menu's job.
+                let here = self.dock.location(id).map(|(s, _)| s) == Some(side);
+                if !here {
+                    self.dock.dock(id, side, usize::MAX);
+                } else if self.dock_panel_visible(id) {
+                    let task = self.dock_set_open(id, false);
+                    self.save_config();
+                    return task;
+                }
+                self.dock_edge_menu = None;
+                let task = self.dock_set_open(id, true);
+                self.save_config();
+                return task;
+            }
+            DockMsg::AutoCollapseToggle(id) => {
+                // Docked: auto-hide for the whole edge; floating: this pallet.
+                if self.dock.toggle_auto_hide(id) {
+                    self.dock_peek = None;
+                }
+                self.save_config();
+            }
+            DockMsg::Close(id) => return self.dock_set_open(id, false),
+            DockMsg::Hover(_)
+            | DockMsg::HoverEnd(_)
+            | DockMsg::HoverExit
+            | DockMsg::HoverStay
+            | DockMsg::HoverSettled(_) => return self.dock_hover(m),
+            DockMsg::DragMove(point) => self.dock_drag_move(point),
+            DockMsg::DragRelease => self.dock_drag_release(),
+        }
+        iced::Task::none()
+    }
+
+    /// Pointer entering / leaving strip icons, edge columns and floating
+    /// frames, and the delayed auto-hide reveal / hide that follows.
+    fn dock_hover(&mut self, m: crate::ui::dock::DockMsg) -> iced::Task<Message> {
+        use crate::ui::dock::{DockMsg, HoverPending};
+        match m {
+            DockMsg::Hover(id) => {
+                self.dock_icon_hover = Some(id);
+                // Only an auto-hiding edge (or floating pallet) reacts to
+                // hover: after a short rest it reveals the hovered pallet's
+                // group. Otherwise groups switch on click. Ignored mid-drag,
+                // when the pointer is over the preview rather than the strip.
+                if self.dock_drag.is_none() && self.dock.auto_hides(id) {
+                    if self.dock_peek == Some(id) {
+                        self.dock_hover_cancel();
+                    } else {
+                        return self.dock_hover_arm(HoverPending::Reveal(id));
+                    }
+                }
+            }
+            DockMsg::HoverEnd(id) => {
+                if self.dock_icon_hover == Some(id) {
+                    self.dock_icon_hover = None;
+                }
+            }
+            DockMsg::HoverExit => {
+                if self.dock_drag.is_none()
+                    && self.dock_peek.is_some_and(|id| self.dock.auto_hides(id))
+                {
+                    return self.dock_hover_arm(HoverPending::Hide);
+                }
+                // Left before a pending reveal ran out: it never happens.
+                self.dock_hover_cancel();
+            }
+            DockMsg::HoverStay => {
+                if self.dock_hover_pending == Some(HoverPending::Hide) {
+                    self.dock_hover_cancel();
+                }
+            }
+            DockMsg::HoverSettled(gen) => {
+                if gen == self.dock_hover_gen && self.dock_drag.is_none() {
+                    match self.dock_hover_pending.take() {
+                        Some(HoverPending::Reveal(id)) if self.dock.auto_hides(id) => {
+                            self.dock_reveal(id)
+                        }
+                        Some(HoverPending::Hide)
+                            if self.dock_peek.is_some_and(|id| self.dock.auto_hides(id)) =>
+                        {
+                            self.dock_peek = None;
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            _ => {}
+        }
+        iced::Task::none()
+    }
+
+    /// Pointer released: land what was dragged and save a changed layout.
+    fn dock_drag_release(&mut self) {
+        use crate::ui::dock::{DockDrag, DropTarget, FloatPanel};
+        let mut changed = false;
+        match self.dock_drag.take() {
+            Some(DockDrag::Move {
+                group: Some((side, gi)),
+                target: Some(DropTarget::Edge { side: to, index }),
+                ..
+            }) => changed = self.dock.move_group(side, gi, to, index),
+            Some(DockDrag::Move {
+                panel,
+                group: None,
+                target: Some(target),
+                ..
+            }) => {
+                changed = match target {
+                    DropTarget::Edge { side, index } => self.dock.dock(panel, side, index),
+                    DropTarget::Join { side, group, index } => {
+                        self.dock.join_group(panel, side, group, index)
+                    }
+                    DropTarget::Float { x, y } => {
+                        let (w, h) = self.dock_float_size(panel);
+                        // A floating panel keeps its docking choice.
+                        let docking = self.dock.float_rect(panel).is_none_or(|f| f.docking);
+                        self.dock.float(FloatPanel {
+                            docking,
+                            ..FloatPanel::new(panel, x, y, w, h)
+                        })
+                    }
+                };
+            }
+            Some(DockDrag::Move { .. } | DockDrag::LayerColumn) | None => {}
+            Some(DockDrag::Width(_) | DockDrag::Split { .. } | DockDrag::FloatSize { .. }) => {
+                changed = true;
+            }
+        }
+        if changed {
+            self.save_config();
+        }
+        self.dock_drag_last = None;
+        self.xref_col_drag = None;
+        self.xref_col_last = None;
+        self.xref_split_drag = false;
+    }
+
+    /// Pointer motion while something in the dock is dragged.
+    fn dock_drag_move(&mut self, point: iced::Point) {
+        // NOTE: xref column drags intentionally do NOT ride this path: its
+        // points live in workspace space while the header tracker reports
+        // header-local points, and mixing the two produced a one-time jump
+        // plus a stuck drag. Column moves arrive via Message::XrefColMove
+        // only.
+        use crate::app::config::DockSide;
+        use crate::ui::dock::{DockDrag, DropTarget};
+        let last = self.dock_drag_last.replace(point);
+        let Some(drag) = self.dock_drag else {
+            return;
+        };
+        match drag {
+            DockDrag::Move {
+                panel,
+                group,
+                origin,
+                target,
+                grab,
+            } => {
+                let origin = origin.unwrap_or(point);
+                let moved = (point.x - origin.x).hypot(point.y - origin.y);
+                let started = target.is_some() || moved >= DOCK_DRAG_THRESHOLD;
+                // Hold a floating panel where it was grabbed; a docked one by
+                // its title bar.
+                let grab = if target.is_none() && started {
+                    match self.dock.float_rect(panel) {
+                        Some(f) => iced::Vector::new(origin.x - f.x, origin.y - f.y),
+                        None => iced::Vector::new(
+                            (self.dock.width(panel, self.win_size.0) * 0.5).min(120.0),
+                            14.0,
+                        ),
+                    }
+                } else {
+                    grab
+                };
+                let target = if started {
+                    // A floating panel that may not dock only floats.
+                    let found = match self.dock.float_rect(panel) {
+                        Some(f) if !f.docking => self.dock_float_target(point, grab),
+                        _ => self.dock_drop_target(point, grab),
+                    };
+                    // A whole group only moves between group positions: it
+                    // cannot join another group or float.
+                    match (group, found) {
+                        (Some(_), found @ DropTarget::Edge { .. }) | (None, found) => Some(found),
+                        (Some(_), _) => None,
+                    }
+                } else {
+                    target
+                };
+                self.dock_drag = Some(DockDrag::Move {
+                    panel,
+                    group,
+                    origin: Some(origin),
+                    target,
+                    grab,
+                });
+            }
+            DockDrag::Split {
+                side,
+                group,
+                upper,
+                lower,
+            } => {
+                let Some(last) = last else { return };
+                let Some(weights) = self.dock.groups(side).get(group).map(|g| &g.weights) else {
+                    return;
+                };
+                let (_, avail) = self.dock_workspace_size();
+                let total: f32 = self
+                    .dock_slot_spans(side)
+                    .iter()
+                    .filter_map(|(i, _, _)| weights.get(*i))
+                    .sum();
+                if avail > 0.0 && total > 0.0 {
+                    let per_px = total / avail;
+                    self.dock.shift_split(
+                        side,
+                        group,
+                        upper,
+                        lower,
+                        (point.y - last.y) * per_px,
+                        crate::ui::dock::GROUP_MIN_H * per_px,
+                    );
+                }
+            }
+            DockDrag::FloatSize { panel, from_left } => {
+                let (Some(last), Some(f)) = (last, self.dock.float_rect(panel)) else {
+                    return;
+                };
+                let dx = point.x - last.x;
+                self.dock.resize_float(
+                    panel,
+                    if from_left { f.w - dx } else { f.w + dx },
+                    f.h + point.y - last.y,
+                    from_left,
+                );
+            }
+            DockDrag::LayerColumn => {
+                let Some(last) = last else { return };
+                self.layer_name_col_w =
+                    (self.layer_name_col_w + point.x - last.x).clamp(60.0, 640.0);
+            }
+            DockDrag::Width(id) => {
+                let Some(last) = last else { return };
+                // The divider sizes the docked pallet's group.
+                if let Some((side, gi)) = self.dock.location(id) {
+                    let dx = point.x - last.x;
+                    let delta = if side == DockSide::Left { dx } else { -dx };
+                    let cur = self.dock_group_width(side, gi) + delta;
+                    self.dock.set_group_width(side, gi, cur);
+                }
+            }
+        }
+    }
+
+    /// Start `drag`, peeking `peek` (a pallet being dragged or resized stays
+    /// shown on an auto-hiding edge).
+    fn dock_begin(
+        &mut self,
+        drag: crate::ui::dock::DockDrag,
+        peek: Option<crate::ui::dock::PanelId>,
+    ) {
+        if let crate::ui::dock::DockDrag::Move { panel, .. } = drag {
+            self.dock.raise_float(panel);
+        }
+        self.dock_drag = Some(drag);
+        self.dock_drag_last = None;
+        self.dock_edge_menu = None;
+        self.dock_float_menu = None;
+        if peek.is_some() {
+            self.dock_peek = peek;
+        }
+    }
+
+    /// Arm a delayed reveal or hide; it applies when its timer reports back
+    /// unless a newer hover superseded it.
+    fn dock_hover_arm(&mut self, target: crate::ui::dock::HoverPending) -> iced::Task<Message> {
+        self.dock_hover_gen = self.dock_hover_gen.wrapping_add(1);
+        self.dock_hover_pending = Some(target);
+        let gen = self.dock_hover_gen;
+        iced::Task::perform(hover_delay(), move |()| {
+            Message::Dock(crate::ui::dock::DockMsg::HoverSettled(gen))
+        })
+    }
+
+    /// Drop any pending delayed reveal / hide.
+    fn dock_hover_cancel(&mut self) {
+        self.dock_hover_gen = self.dock_hover_gen.wrapping_add(1);
+        self.dock_hover_pending = None;
+    }
+
+    /// Bring `id` into view: show its group on its edge and, where it
+    /// auto-hides, keep it revealed until the pointer leaves.
+    pub(crate) fn dock_reveal(&mut self, id: crate::ui::dock::PanelId) {
+        self.dock.show_group_of(id);
+        self.dock_peek = Some(id);
+    }
+
+    /// Open or close pallet `id`, running its usual open path (refreshes,
+    /// ribbon highlight) or close path. An opened pallet is revealed where
+    /// the layout has it.
+    pub(crate) fn dock_set_open(
+        &mut self,
+        id: crate::ui::dock::PanelId,
+        open: bool,
+    ) -> iced::Task<Message> {
+        use crate::ui::dock::{DockDrag, PanelId};
+        let mut task = iced::Task::none();
+        if open {
+            if !self.dock_panel_visible(id) {
+                match id {
+                    PanelId::Properties => {
+                        self.show_properties = true;
+                        self.ribbon.set_properties(true);
+                    }
+                    PanelId::BlockPalette => self.open_blocks_palette(None),
+                    PanelId::ExternalReferences => {
+                        self.show_external_references = true;
+                        self.refresh_xref_manager();
+                    }
+                    PanelId::Browser => self.show_browser = true,
+                    PanelId::NodeGraph => {
+                        task = self.on_graph(crate::ui::node_graph::GraphMsg::Toggle);
+                    }
+                    PanelId::PointCloudManager => self.pc_manager.show = true,
+                    PanelId::Count => self.set_count_palette(true),
+                    PanelId::SheetSetManager => self.show_sheet_set_manager(true),
+                    PanelId::Layers => {
+                        self.sync_ribbon_layers();
+                        self.show_layers = true;
+                    }
+                }
+            }
+            self.dock_reveal(id);
+            return task;
+        }
+        match id {
+            PanelId::BlockPalette => {
+                self.show_block_palette = false;
+                self.block_palette.placing = None;
+            }
+            PanelId::ExternalReferences => self.show_external_references = false,
+            PanelId::Browser => self.show_browser = false,
+            PanelId::NodeGraph => self.show_node_graph = false,
+            PanelId::PointCloudManager => self.pc_manager.show = false,
+            PanelId::Count => {
+                self.count_palette.show = false;
+                self.ribbon.set_count_palette(false);
+            }
+            PanelId::SheetSetManager => {
+                self.sheet_set.show = false;
+                self.ribbon.set_sheet_set(false);
+            }
+            PanelId::Properties => {
+                self.show_properties = false;
+                self.ribbon.set_properties(false);
+            }
+            PanelId::Layers => {
+                self.show_layers = false;
+                self.ribbon.deactivate_tool_if("LAYERS");
+            }
+        }
+        self.dock_unpeek(id);
+        // A closed pallet cannot stay held by the pointer.
+        let held = match self.dock_drag {
+            Some(DockDrag::Move { panel, .. } | DockDrag::Width(panel)) => panel == id,
+            _ => false,
+        };
+        if held {
+            self.dock_drag = None;
+        }
+        task
+    }
+
+    /// Show `id` where the layout has it, first docking it on the right edge
+    /// when it has no place yet (opened for the first time, or never moved).
+    pub(crate) fn dock_open_at_default(&mut self, id: crate::ui::dock::PanelId) {
+        if !self.dock.is_placed(id) {
+            self.dock
+                .dock(id, crate::app::config::DockSide::Right, usize::MAX);
+        }
+        self.dock_reveal(id);
+    }
+
+    /// Open the Layer Manager pallet (LAYERS). The first time it floats over
+    /// the middle of the drawing, where the dialog it replaced used to open;
+    /// after that it opens wherever the user left it.
+    pub(crate) fn open_layers_pallet(&mut self) {
+        use crate::ui::dock::{FloatPanel, PanelId};
+        self.sync_ribbon_layers();
+        self.show_layers = true;
+        if !self.dock.is_placed(PanelId::Layers) {
+            let (ww, wh) = self.dock_workspace_size();
+            let (w, h) = self.dock_float_size(PanelId::Layers);
+            let (x, y) = (((ww - w) * 0.5).max(0.0), ((wh - h) * 0.5).max(0.0));
+            self.dock
+                .float(FloatPanel::new(PanelId::Layers, x, y, w, h));
+            self.save_config();
+        }
+        self.dock.raise_float(PanelId::Layers);
+        self.dock_reveal(PanelId::Layers);
+    }
+
+    /// Stop revealing `id` (it closed).
+    pub(crate) fn dock_unpeek(&mut self, id: crate::ui::dock::PanelId) {
+        if self.dock_peek == Some(id) {
+            self.dock_peek = None;
+        }
+    }
+
+    /// Whether `id` is currently rendered (not closed, not on the start screen /
+    /// clean-screen viewport). Mirrors the visibility filter the edge column
+    /// renderer applies before building each side's stack.
+    pub(crate) fn dock_panel_visible(&self, id: crate::ui::dock::PanelId) -> bool {
+        use crate::ui::dock::PanelId;
+        if self.tabs[self.active_tab].is_start || self.clean_screen {
+            return false;
+        }
+        match id {
+            PanelId::Properties => self.show_properties,
+            PanelId::BlockPalette => self.show_block_palette,
+            PanelId::ExternalReferences => self.show_external_references,
+            PanelId::Browser => self.show_browser,
+            PanelId::NodeGraph => self.show_node_graph,
+            PanelId::PointCloudManager => self.pc_manager.show,
+            PanelId::Count => self.count_palette.show,
+            PanelId::SheetSetManager => self.sheet_set.show,
+            PanelId::Layers => self.show_layers,
+        }
+    }
+
+    /// Size of the workspace the dock lays out in: window width by viewport
+    /// height.
+    pub(crate) fn dock_workspace_size(&self) -> (f32, f32) {
+        (
+            self.win_size.0,
+            self.tabs[self.active_tab]
+                .scene
+                .selection
+                .borrow()
+                .view
+                .vp_size
+                .1,
+        )
+    }
+
+    /// The open pallets of group `gi` on `side`, top → bottom. Closed
+    /// pallets keep their place but take no space, so a group with none open
+    /// is not drawn at all.
+    pub(crate) fn dock_group_visible(
+        &self,
+        side: crate::app::config::DockSide,
+        gi: usize,
+    ) -> Vec<crate::ui::dock::PanelId> {
+        // A stale index (a message from before the layout changed) reads as
+        // an empty group rather than a crash.
+        self.dock
+            .groups(side)
+            .get(gi)
+            .into_iter()
+            .flat_map(|g| g.panels.iter().copied())
+            .filter(|id| self.dock_panel_visible(*id))
+            .collect()
+    }
+
+    /// Indices of the groups on `side` with an open pallet (listed in the
+    /// icon strip).
+    pub(crate) fn dock_visible_groups(&self, side: crate::app::config::DockSide) -> Vec<usize> {
+        (0..self.dock.groups(side).len())
+            .filter(|gi| !self.dock_group_visible(side, *gi).is_empty())
+            .collect()
+    }
+
+    /// The group `side` draws: the one it shows, or the first with an open
+    /// pallet when that one has none.
+    pub(crate) fn dock_shown_group(&self, side: crate::app::config::DockSide) -> Option<usize> {
+        let visible = self.dock_visible_groups(side);
+        let shown = self.dock.shown(side);
+        if visible.contains(&shown) {
+            Some(shown)
+        } else {
+            visible.first().copied()
+        }
+    }
+
+    /// Whether `side` draws its shown group beside the icon strip: always,
+    /// unless the edge auto-hides and none of the group's icons is hovered.
+    pub(crate) fn dock_edge_expanded(&self, side: crate::app::config::DockSide) -> bool {
+        let Some(gi) = self.dock_shown_group(side) else {
+            return false;
+        };
+        !self.dock.edge_auto_hide(side)
+            || self
+                .dock_peek
+                .is_some_and(|e| self.dock_group_visible(side, gi).contains(&e))
+    }
+
+    /// On-screen width of group `gi` on `side`.
+    pub(crate) fn dock_group_width(&self, side: crate::app::config::DockSide, gi: usize) -> f32 {
+        self.dock.group_width_px(side, gi, self.win_size.0)
+    }
+
+    /// Width of the pallet column beside `side`'s icon strip: the shown
+    /// group's width, or nothing when it is hidden.
+    pub(crate) fn dock_column_width(&self, side: crate::app::config::DockSide) -> f32 {
+        match self.dock_shown_group(side) {
+            Some(gi) if self.dock_edge_expanded(side) => self.dock_group_width(side, gi),
+            _ => 0.0,
+        }
+    }
+
+    /// The icon strip of `side`: each listed group's place, and the top of
+    /// the + button.
+    pub(crate) fn dock_strip_layout(
+        &self,
+        side: crate::app::config::DockSide,
+    ) -> (Vec<crate::ui::dock::StripGroup>, f32) {
+        let groups: Vec<(usize, usize)> = self
+            .dock_visible_groups(side)
+            .into_iter()
+            .map(|gi| (gi, self.dock_group_visible(side, gi).len()))
+            .collect();
+        crate::ui::dock::strip_layout(&groups)
+    }
+
+    /// The open pallets of `side`'s shown group, each as (position in the
+    /// group, top, bottom) in the workspace.
+    pub(crate) fn dock_slot_spans(
+        &self,
+        side: crate::app::config::DockSide,
+    ) -> Vec<(usize, f32, f32)> {
+        match self.dock_shown_group(side) {
+            Some(gi) => self.dock_open_spans(&self.dock.groups(side)[gi], None),
+            None => Vec::new(),
+        }
+    }
+
+    /// The open pallets of `group` (plus `extra`, a pallet about to land
+    /// there), each as (position in the group, top, bottom) down the
+    /// workspace height.
+    pub(crate) fn dock_open_spans(
+        &self,
+        group: &crate::ui::dock::DockGroup,
+        extra: Option<crate::ui::dock::PanelId>,
+    ) -> Vec<(usize, f32, f32)> {
+        let (_, avail) = self.dock_workspace_size();
+        let open: Vec<usize> = (0..group.panels.len())
+            .filter(|i| {
+                let id = group.panels[*i];
+                Some(id) == extra || self.dock_panel_visible(id)
+            })
+            .collect();
+        let weights: Vec<f32> = open.iter().map(|i| group.weights[*i]).collect();
+        open.into_iter()
+            .zip(crate::ui::dock::slot_spans(&weights, avail))
+            .map(|(i, (top, bottom))| (i, top, bottom))
+            .collect()
+    }
+
+    /// Size a panel takes when floated: its current floating size, or its
+    /// docked width by a comfortable share of the workspace height.
+    pub(crate) fn dock_float_size(&self, id: crate::ui::dock::PanelId) -> (f32, f32) {
+        if let Some(f) = self.dock.float_rect(id) {
+            return (f.w, f.h);
+        }
+        let (_, avail) = self.dock_workspace_size();
+        (
+            self.dock.width(id, self.win_size.0),
+            (avail * 0.6).clamp(crate::ui::dock::FLOAT_MIN_H, 520.0),
+        )
+    }
+
+    /// Where a dragged pallet lands if released at workspace point `p`:
+    /// on an edge's icon strip it joins a group between its icons or starts a
+    /// new group; over the shown group's pallets it stacks above / below the
+    /// one under the pointer; on an empty edge it starts a group; anywhere
+    /// else it floats, held at `grab` from its top-left corner.
+    pub(crate) fn dock_drop_target(
+        &self,
+        p: iced::Point,
+        grab: iced::Vector,
+    ) -> crate::ui::dock::DropTarget {
+        use crate::app::config::DockSide;
+        use crate::ui::dock::{DropTarget, StripHit, DOCK_EDGE_ZONE, DOCK_STRIP_W};
+        let (ww, _) = self.dock_workspace_size();
+        for side in [DockSide::Left, DockSide::Right] {
+            let listed = !self.dock_visible_groups(side).is_empty();
+            let from_edge = match side {
+                DockSide::Left => p.x,
+                DockSide::Right => ww - p.x,
+            };
+            if !listed {
+                if from_edge <= DOCK_EDGE_ZONE {
+                    return DropTarget::Edge {
+                        side,
+                        index: self.dock.groups(side).len(),
+                    };
+                }
+                continue;
+            }
+            // Over the icon strip.
+            if from_edge <= DOCK_STRIP_W {
+                let (layout, _) = self.dock_strip_layout(side);
+                return match crate::ui::dock::strip_hit(p.y, &layout) {
+                    StripHit::NewGroup(at) => DropTarget::Edge {
+                        side,
+                        index: at.unwrap_or(self.dock.groups(side).len()),
+                    },
+                    StripHit::Join { group, index } => {
+                        // Map the gap among open pallets to a position among
+                        // all of the group's pallets.
+                        let open = self.dock_group_visible(side, group);
+                        let all = &self.dock.groups(side)[group].panels;
+                        let index = open
+                            .get(index)
+                            .and_then(|t| all.iter().position(|a| a == t))
+                            .unwrap_or(all.len());
+                        DropTarget::Join { side, group, index }
+                    }
+                };
+            }
+            // Over the shown group's pallets: above or below the one there.
+            if from_edge <= DOCK_STRIP_W + self.dock_column_width(side) {
+                let gi = self.dock_shown_group(side).expect("listed edge");
+                let spans = self.dock_slot_spans(side);
+                if let Some(&(pos, top, bottom)) = spans
+                    .iter()
+                    .find(|(_, _, bottom)| p.y < *bottom)
+                    .or(spans.last())
+                {
+                    let index = if p.y < (top + bottom) * 0.5 {
+                        pos
+                    } else {
+                        pos + 1
+                    };
+                    return DropTarget::Join {
+                        side,
+                        group: gi,
+                        index,
+                    };
+                }
+            }
+        }
+        self.dock_float_target(p, grab)
+    }
+
+    /// Floating at workspace point `p`, held at `grab` from its top-left
+    /// corner (kept on the workspace).
+    pub(crate) fn dock_float_target(
+        &self,
+        p: iced::Point,
+        grab: iced::Vector,
+    ) -> crate::ui::dock::DropTarget {
+        let (ww, wh) = self.dock_workspace_size();
+        let x = (p.x - grab.x).clamp(0.0, (ww - 60.0).max(0.0));
+        let y = (p.y - grab.y).clamp(0.0, (wh - 30.0).max(0.0));
+        crate::ui::dock::DropTarget::Float { x, y }
+    }
+}

src/app/mod.rs

@@ -14,6 +14,7 @@ pub(crate) mod commands;
 pub(crate) mod dim_viewport;
 #[cfg(test)]
 mod dimension_preview_tests;
+mod dock;
 mod document;
 mod drafting_settings;
 pub(crate) mod expr_eval;
@@ -814,6 +815,8 @@ pub(super) struct OpenCADStudio {
     render_mode_preview: Option<codec::entities::ViewportRenderMode>,
     /// Whether the Properties panel is shown on the left (PROPERTIES).
     show_properties: bool,
+    /// The Layer Manager pallet (LAYERS) is open.
+    pub(crate) show_layers: bool,
     /// Docked Insert Block panel visibility.
     pub(crate) show_block_palette: bool,
     /// Node graph overlay over the viewport.
@@ -843,17 +846,33 @@ pub(super) struct OpenCADStudio {
     pub(crate) bg_picker: Option<BgTarget>,
     /// General edge-stack dock layout for the side panels.
     pub(crate) dock: crate::ui::dock::DockState,
-    /// Which panel is currently floated at full height (hovered, or a pinned
+    /// Pallet revealed although it auto-hides (its edge's group, or its
-    /// panel on top).
+    /// floating frame): hovered, being dragged, or just opened. Cleared when
-    pub(crate) dock_expanded: Option<crate::ui::dock::PanelId>,
+    /// the pointer leaves.
-    /// Panel currently being dragged between sides / reordered.
+    pub(crate) dock_peek: Option<crate::ui::dock::PanelId>,
-    pub(crate) dock_dragging: Option<crate::ui::dock::PanelId>,
+    /// Reveal or hide waiting out the hover delay, with the generation its
-    /// Panel currently being width-resized.
+    /// timer carries; any newer hover supersedes it.
-    pub(crate) dock_resizing: Option<crate::ui::dock::PanelId>,
+    pub(crate) dock_hover_pending: Option<crate::ui::dock::HoverPending>,
-    /// Last pointer position during a drag / resize.
+    pub(crate) dock_hover_gen: u64,
+    /// What the pointer is dragging in the dock (pallet, group, width,
+    /// splitter, floating size, Layer Manager column).
+    pub(crate) dock_drag: Option<crate::ui::dock::DockDrag>,
+    /// Pallet whose strip icon (or floating frame) the pointer is over.
+    pub(crate) dock_icon_hover: Option<crate::ui::dock::PanelId>,
+    /// Last pointer position during a dock drag.
     pub(crate) dock_drag_last: Option<iced::Point>,
-    /// Live drag target (side + index), shown as a highlight while dragging.
+    /// Docked panel whose title bar the pointer is over (shows pin / close).
-    pub(crate) dock_drag_target: Option<(crate::app::config::DockSide, usize)>,
+    pub(crate) dock_title_hover: Option<crate::ui::dock::PanelId>,
+    /// Edge whose icon-strip pallet menu (+) is open.
+    pub(crate) dock_edge_menu: Option<crate::app::config::DockSide>,
+    /// Floating pallet whose title-bar right-click menu is open.
+    pub(crate) dock_float_menu: Option<crate::ui::dock::PanelId>,
+    /// Pointer position over a floating title bar (bar-local), and where
+    /// its open menu was asked for.
+    pub(crate) dock_float_pointer: iced::Point,
+    pub(crate) dock_float_menu_at: iced::Point,
+    /// Group whose edge band (group grip) the pointer is over.
+    pub(crate) dock_grip_hover: Option<(crate::app::config::DockSide, usize)>,
     /// Reference-table column currently being width-resized (column index),
     /// with the last pointer position. Mirrors the Layers Name-column drag.
     pub(crate) xref_col_drag: Option<usize>,
@@ -942,9 +961,6 @@ pub(super) struct OpenCADStudio {
     modal_drag_last: Option<Point>,
     /// True while the modal title bar is held (a drag is in progress).
     modal_dragging: bool,
-    /// Layer Manager: dragging the Name-column divider (width follows the
-    /// shared ModalDragMove flow).
-    layer_col_dragging: bool,
     /// Layer Manager Name column width in px, adjusted by the divider drag.
     layer_name_col_w: f32,
     /// How far the user has dragged the modal's corner resize grip from the
@@ -1951,7 +1967,6 @@ pub enum ModalKind {
     PluginManager,
     UpdateNotice,
     DonationPrompt,
-    Layers,
     LayerStateManager,
     LayerTranslator,
     DrawingUnits,
@@ -4293,6 +4308,7 @@ impl OpenCADStudio {
             render_mode_menu_open: false,
             render_mode_preview: None,
             show_properties: true,
+            show_layers: false,
             show_block_palette: false,
             show_node_graph: false,
             property_target_override: None,
@@ -4308,11 +4324,18 @@ impl OpenCADStudio {
             block_palette: Default::default(),
             xref_manager: Default::default(),
             dock: Default::default(),
-            dock_expanded: None,
+            dock_peek: None,
-            dock_dragging: None,
+            dock_hover_pending: None,
-            dock_resizing: None,
+            dock_hover_gen: 0,
+            dock_float_menu: None,
+            dock_float_pointer: iced::Point::ORIGIN,
+            dock_float_menu_at: iced::Point::ORIGIN,
+            dock_drag: None,
             dock_drag_last: None,
-            dock_drag_target: None,
+            dock_title_hover: None,
+            dock_edge_menu: None,
+            dock_grip_hover: None,
+            dock_icon_hover: None,
             xref_col_drag: None,
             xref_col_last: None,
             xref_split_drag: false,
@@ -4349,7 +4372,6 @@ impl OpenCADStudio {
             modal_offset: iced::Vector::ZERO,
             modal_drag_last: None,
             modal_dragging: false,
-            layer_col_dragging: false,
             layer_name_col_w: 130.0,
             modal_resize: iced::Vector::ZERO,
             modal_content_size: None,

src/app/node_graph.rs

@@ -188,11 +188,7 @@ impl OpenCADStudio {
                     // The node library docks on the right on first use; after
                     // that it stays wherever the user moved it.
                     let id = crate::ui::dock::PanelId::NodeGraph;
-                    if self.dock.location(id).is_none() {
+                    self.dock_open_at_default(id);
-                        self.dock
-                            .dock(id, crate::app::config::DockSide::Right, usize::MAX);
-                    }
-                    self.dock_expanded = Some(id);
                     return self.graph_run(i);
                 }
             }

src/app/update/blocks_palette.rs

@@ -134,7 +134,7 @@ impl OpenCADStudio {
     /// BLOCKSPALETTE: open (expanded) on `tab`, or on the tab it was left on.
     pub(crate) fn open_blocks_palette(&mut self, tab: Option<Tab>) {
         self.show_block_palette = true;
-        self.dock_expanded = Some(crate::ui::dock::PanelId::BlockPalette);
+        self.dock_reveal(crate::ui::dock::PanelId::BlockPalette);
         self.show_block_palette_tab(tab.unwrap_or(self.block_palette.tab));
     }
 

src/app/update/dialog.rs

@@ -542,195 +542,6 @@ impl OpenCADStudio {
         Ok(name)
     }
 
-    /// Dock chrome interaction (grab / pin / resize / hover / move) applied to
-    /// whichever panel the message names.
-    pub(super) fn on_dock(&mut self, m: crate::ui::dock::DockMsg) -> iced::Task<Message> {
-        use crate::app::config::DockSide;
-        use crate::ui::dock::{DockMsg, PanelId};
-        match m {
-            DockMsg::DockGrab(id) => {
-                self.dock_dragging = Some(id);
-                self.dock_resizing = None;
-                self.dock_drag_last = None;
-                self.dock_drag_target = self.dock.location(id);
-                self.dock_expanded = Some(id);
-                iced::Task::none()
-            }
-            DockMsg::ResizeGrab(id) => {
-                self.dock_resizing = Some(id);
-                self.dock_dragging = None;
-                self.dock_drag_last = None;
-                self.dock_drag_target = None;
-                self.dock_expanded = Some(id);
-                iced::Task::none()
-            }
-            DockMsg::WidthReset(id) => {
-                self.dock.reset_width(id);
-                self.save_config();
-                iced::Task::none()
-            }
-            DockMsg::AutoCollapseToggle(id) => {
-                let on = !self.dock.auto_collapse(id);
-                self.dock.set_auto_collapse(id, on);
-                self.dock_expanded = if on { None } else { Some(id) };
-                self.save_config();
-                iced::Task::none()
-            }
-            DockMsg::Close(id) => {
-                match id {
-                    PanelId::BlockPalette => {
-                        self.show_block_palette = false;
-                        self.block_palette.placing = None;
-                    }
-                    PanelId::ExternalReferences => {
-                        self.show_external_references = false;
-                    }
-                    PanelId::Browser => {
-                        self.show_browser = false;
-                    }
-                    PanelId::NodeGraph => {
-                        self.show_node_graph = false;
-                    }
-                    PanelId::PointCloudManager => {
-                        self.pc_manager.show = false;
-                    }
-                    PanelId::Count => {
-                        self.count_palette.show = false;
-                        self.ribbon.set_count_palette(false);
-                    }
-                    PanelId::SheetSetManager => {
-                        self.sheet_set.show = false;
-                        self.ribbon.set_sheet_set(false);
-                    }
-                    PanelId::Properties => {
-                        self.show_properties = false;
-                        self.ribbon.set_properties(false);
-                    }
-                }
-                if self.dock_expanded == Some(id) {
-                    self.dock_expanded = None;
-                }
-                if self.dock_dragging == Some(id) {
-                    self.dock_dragging = None;
-                }
-                if self.dock_resizing == Some(id) {
-                    self.dock_resizing = None;
-                }
-                iced::Task::none()
-            }
-            DockMsg::Hover(id) => {
-                // Ignored while dragging/resizing: the pointer is over the
-                // drag preview, not a rail, so a hover must not collapse the
-                // panel being dragged or repoint the resize target.
-                if self.dock_dragging.is_none() && self.dock_resizing.is_none() {
-                    self.dock_expanded = Some(id);
-                }
-                iced::Task::none()
-            }
-            DockMsg::HoverExit => {
-                if self.dock_dragging.is_none() && self.dock_resizing.is_none() {
-                    if let Some(id) = self.dock_expanded {
-                        if self.dock.auto_collapse(id) {
-                            self.dock_expanded = None;
-                        }
-                    }
-                }
-                iced::Task::none()
-            }
-            DockMsg::DragMove(point) => {
-                // NOTE: xref column drags intentionally do NOT ride this
-                // path: its points live in workspace space while the header
-                // tracker reports header-local points, and mixing the two
-                // produced a one-time jump plus a stuck drag. Column moves
-                // arrive via Message::XrefColMove only.
-                if self.dock_dragging.is_some() {
-                    let avail = self.tabs[self.active_tab]
-                        .scene
-                        .selection
-                        .borrow()
-                        .view
-                        .vp_size
-                        .1;
-                    let side = if point.x < self.win_size.0 * 0.5 {
-                        DockSide::Left
-                    } else {
-                        DockSide::Right
-                    };
-                    let index = crate::ui::dock::drop_index(
-                        point.y,
-                        std::cmp::max(self.dock_visible_len(side), 1),
-                        avail,
-                    );
-                    self.dock_drag_target = Some((side, index));
-                } else if let Some(id) = self.dock_resizing {
-                    if let Some(last) = self.dock_drag_last {
-                        let dx = point.x - last.x;
-                        let delta = match self.dock.location(id) {
-                            Some((DockSide::Left, _)) => dx,
-                            _ => -dx,
-                        };
-                        let cur = self.dock.settings(id).width + delta;
-                        self.dock.set_width(id, cur);
-                    }
-                }
-                if self.dock_dragging.is_some() || self.dock_resizing.is_some() {
-                    self.dock_drag_last = Some(point);
-                }
-                iced::Task::none()
-            }
-            DockMsg::DragRelease => {
-                if let Some(id) = self.dock_dragging {
-                    if let Some((side, index)) = self.dock_drag_target {
-                        if self.dock.dock(id, side, index) {
-                            self.save_config();
-                        }
-                    }
-                }
-                self.dock_dragging = None;
-                self.dock_resizing = None;
-                self.dock_drag_last = None;
-                self.dock_drag_target = None;
-                self.xref_col_drag = None;
-                self.xref_col_last = None;
-                self.xref_split_drag = false;
-                iced::Task::none()
-            }
-        }
-    }
-
-    /// Whether `id` is currently rendered (not closed, not on the start screen /
-    /// clean-screen viewport). Mirrors the visibility filter the edge column
-    /// renderer applies before building each side's stack.
-    pub(crate) fn dock_panel_visible(&self, id: crate::ui::dock::PanelId) -> bool {
-        use crate::ui::dock::PanelId;
-        if self.tabs[self.active_tab].is_start || self.clean_screen {
-            return false;
-        }
-        match id {
-            PanelId::Properties => self.show_properties,
-            PanelId::BlockPalette => self.show_block_palette,
-            PanelId::ExternalReferences => self.show_external_references,
-            PanelId::Browser => self.show_browser,
-            PanelId::NodeGraph => self.show_node_graph,
-            PanelId::PointCloudManager => self.pc_manager.show,
-            PanelId::Count => self.count_palette.show,
-            PanelId::SheetSetManager => self.sheet_set.show,
-        }
-    }
-
-    /// Number of panels currently rendered on `side`. Closed panels keep their
-    /// stack slot but take no vertical space, so drag preview geometry must
-    /// size slots against only the panels that are actually visible.
-    pub(crate) fn dock_visible_len(&self, side: crate::app::config::DockSide) -> usize {
-        let ids: &[crate::ui::dock::PanelId] = match side {
-            crate::app::config::DockSide::Left => &self.dock.left,
-            crate::app::config::DockSide::Right => &self.dock.right,
-        };
-        ids.iter()
-            .filter(|id| self.dock_panel_visible(**id))
-            .count()
-    }
-
     /// Rebuild the Reference Manager's entry list from the active drawing.
     /// Uses the tab's session sets (unloaded + stat baseline) so CLI and
     /// palette agree; writes fresh load-time mtimes back into the tab's stat
@@ -1605,134 +1416,6 @@ mod tests {
         );
     }
 
-    #[test]
-    fn blockpalette_pin_toggles_autocollapse_and_close_hides() {
-        let mut app = fresh();
-        app.show_block_palette = true;
-        let id = crate::ui::dock::PanelId::BlockPalette;
-        let _ = app.on_dock(crate::ui::dock::DockMsg::AutoCollapseToggle(id));
-        assert!(app.dock.auto_collapse(id), "pin enables auto-collapse");
-        let _ = app.on_dock(crate::ui::dock::DockMsg::AutoCollapseToggle(id));
-        assert!(
-            !app.dock.auto_collapse(id),
-            "second pin disables auto-collapse"
-        );
-        let _ = app.on_dock(crate::ui::dock::DockMsg::Close(id));
-        assert!(!app.show_block_palette, "close dismisses the sidebar");
-    }
-
-    #[test]
-    fn blockpalette_dock_moves_to_other_side_and_persists() {
-        let mut app = fresh();
-        // Tests load the user's persisted config; reset the dock to a known
-        // state so this stays hermetic.
-        app.dock = Default::default();
-        let id = crate::ui::dock::PanelId::BlockPalette;
-        assert_eq!(
-            app.dock.location(id),
-            Some((crate::app::config::DockSide::Right, 0))
-        );
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DockGrab(id));
-        app.win_size = (1600.0, 900.0).into();
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DragMove(iced::Point::new(
-            100.0, 100.0,
-        )));
-        assert_eq!(
-            app.dock_drag_target,
-            Some((crate::app::config::DockSide::Left, 0))
-        );
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DragRelease);
-        assert_eq!(
-            app.dock.location(id),
-            Some((crate::app::config::DockSide::Left, 0))
-        );
-    }
-
-    #[test]
-    fn dock_visible_len_counts_only_rendered_panels() {
-        let mut app = fresh();
-        app.dock = Default::default();
-        app.dock.left = vec![
-            crate::ui::dock::PanelId::BlockPalette,
-            crate::ui::dock::PanelId::Properties,
-        ];
-        // Left: block palette hidden, properties shown -> 1 visible panel.
-        app.show_block_palette = false;
-        app.show_properties = true;
-        assert_eq!(app.dock_visible_len(crate::app::config::DockSide::Left), 1);
-        // Reveal the block palette -> both count.
-        app.show_block_palette = true;
-        assert_eq!(app.dock_visible_len(crate::app::config::DockSide::Left), 2);
-        // A hidden (closed) panel counts for nothing even when stacked.
-        app.show_block_palette = false;
-        assert_eq!(app.dock_visible_len(crate::app::config::DockSide::Left), 1);
-    }
-
-    #[test]
-    fn dock_drag_target_ignores_hidden_panels_on_the_side() {
-        // Reproduce the persisted layout that exposed a half-height ghost: two
-        // panels live in the left stack but the block palette is hidden
-        // (show_block_palette=false), so only Properties renders. Drag geometry
-        // must count only panels that are actually visible.
-        let mut app = fresh();
-        app.dock = Default::default();
-        app.dock.left = vec![
-            crate::ui::dock::PanelId::BlockPalette,
-            crate::ui::dock::PanelId::Properties,
-        ];
-        app.show_block_palette = false;
-        app.show_properties = true;
-        let i = app.active_tab;
-        app.tabs[i].scene.selection.borrow_mut().view.vp_size = (1600.0, 900.0);
-        app.win_size = (1600.0, 900.0).into();
-        let id = crate::ui::dock::PanelId::Properties;
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DockGrab(id));
-        // Pointer near the bottom of the left edge: one visible panel means a
-        // single slot, so every y maps to index 0 (no top/bottom split).
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DragMove(iced::Point::new(
-            100.0, 850.0,
-        )));
-        assert_eq!(
-            app.dock_drag_target,
-            Some((crate::app::config::DockSide::Left, 0))
-        );
-    }
-
-    #[test]
-    fn dock_drag_target_counts_all_visible_panels() {
-        let mut app = fresh();
-        app.dock = Default::default();
-        app.dock.left = vec![
-            crate::ui::dock::PanelId::BlockPalette,
-            crate::ui::dock::PanelId::Properties,
-        ];
-        // Both panels shown: two real slots on the left edge. A pointer near
-        // the bottom maps to the append slot (index == 2).
-        app.show_block_palette = true;
-        app.show_properties = true;
-        let i = app.active_tab;
-        app.tabs[i].scene.selection.borrow_mut().view.vp_size = (1600.0, 900.0);
-        app.win_size = (1600.0, 900.0).into();
-        let id = crate::ui::dock::PanelId::Properties;
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DockGrab(id));
-        let _ = app.on_dock(crate::ui::dock::DockMsg::DragMove(iced::Point::new(
-            100.0, 850.0,
-        )));
-        assert_eq!(
-            app.dock_drag_target,
-            Some((crate::app::config::DockSide::Left, 2))
-        );
-    }
-
-    #[test]
-    fn blockpalette_width_reset() {
-        let mut app = fresh();
-        let id = crate::ui::dock::PanelId::BlockPalette;
-        app.dock.set_width(id, 500.0);
-        let _ = app.on_dock(crate::ui::dock::DockMsg::WidthReset(id));
-        assert_eq!(app.dock.settings(id).width, 260.0);
-    }
-
     #[test]
     fn block_name_from_file_avoids_collisions() {
         let mut app = fresh();

src/app/update/mod.rs

@@ -2608,27 +2608,19 @@ impl OpenCADStudio {
             Message::ScriptLine(line) => self.feed_script_line(&line),
 
             Message::ToggleLayers => {
-                if self.active_modal == Some(super::ModalKind::Layers) {
+                if self.show_layers {
-                    self.ribbon.deactivate_tool_if("LAYERS");
+                    return self.on_dock(crate::ui::dock::DockMsg::Close(
-                    self.active_modal = None;
+                        crate::ui::dock::PanelId::Layers,
-                    self.reset_modal_geometry();
+                    ));
-                } else {
-                    self.sync_ribbon_layers();
-                    self.active_modal = Some(super::ModalKind::Layers);
                 }
+                self.open_layers_pallet();
                 Task::none()
             }
 
             Message::ToggleXrefManager => {
                 self.show_external_references ^= true;
                 if self.show_external_references {
-                    use crate::app::config::DockSide;
+                    self.dock_open_at_default(crate::ui::dock::PanelId::ExternalReferences);
-                    use crate::ui::dock::PanelId;
-                    if self.dock.location(PanelId::ExternalReferences).is_none() {
-                        self.dock
-                            .dock(PanelId::ExternalReferences, DockSide::Right, usize::MAX);
-                    }
-                    self.dock_expanded = Some(PanelId::ExternalReferences);
                     self.refresh_xref_manager();
                 }
                 Task::none()
@@ -6362,8 +6354,11 @@ impl OpenCADStudio {
                     // Ctrl+A in the MText editor selects all of its text.
                     self.mtext_select_all();
                     Task::none()
-                } else if self.active_modal == Some(super::ModalKind::Layers) {
+                } else if self.dock_panel_visible(crate::ui::dock::PanelId::Layers)
-                    // Select every row in the Layer Manager (#236).
+                    && self.tabs[i].layers.selected.is_some()
+                {
+                    // Select every row in the Layer Manager (#236) while the
+                    // user is working in it (a layer row is selected).
                     let n = self.tabs[i].layers.layers.len();
                     self.tabs[i].layers.selected_multi = (0..n).collect();
                     self.tabs[i].layers.selected = (n > 0).then_some(0);
@@ -9144,17 +9139,16 @@ impl OpenCADStudio {
                 Task::none()
             }
             Message::LayerNameColGrab => {
-                // Start a Name-column divider drag; rides ModalDragMove.
+                // Start a Name-column divider drag; the dock's pointer capture
-                self.layer_col_dragging = true;
+                // feeds it (see `on_dock`).
-                self.modal_drag_last = None;
+                self.dock_drag = Some(crate::ui::dock::DockDrag::LayerColumn);
+                self.dock_drag_last = None;
                 Task::none()
             }
             Message::ModalDragMove(p) => {
                 if let Some(last) = self.modal_drag_last {
                     let (dx, dy) = (p.x - last.x, p.y - last.y);
-                    if self.layer_col_dragging {
+                    if self.modal_resizing {
-                        self.layer_name_col_w = (self.layer_name_col_w + dx).clamp(60.0, 640.0);
-                    } else if self.modal_resizing {
                         // The grip sits bottom-right, so dragging out grows the
                         // box. The delta is added to each dialog's natural size,
                         // so clamp it at zero — dragging in past the natural size
@@ -9188,7 +9182,7 @@ impl OpenCADStudio {
                         }
                     }
                 }
-                if self.modal_dragging || self.modal_resizing || self.layer_col_dragging {
+                if self.modal_dragging || self.modal_resizing {
                     self.modal_drag_last = Some(p);
                 }
                 Task::none()
@@ -9196,7 +9190,6 @@ impl OpenCADStudio {
             Message::ModalDragRelease => {
                 self.modal_dragging = false;
                 self.modal_resizing = false;
-                self.layer_col_dragging = false;
                 self.modal_drag_last = None;
                 Task::none()
             }

src/app/view/mod.rs

@@ -9,11 +9,11 @@ use crate::t;
 use crate::ui::wrap_bar::DensitySwap;
 use crate::ui::wrap_bar::WrapFlow;
 use iced::widget::{
-    button, canvas, column, container, mouse_area, pane_grid, responsive, row, scrollable, shader,
+    button, column, container, mouse_area, pane_grid, responsive, row, scrollable, shader, stack,
-    stack, text, Row, Space,
+    text, Row, Space,
 };
 use iced::window;
-use iced::{keyboard, Background, Border, Color, Element, Fill, Length, Subscription, Task, Theme};
+use iced::{keyboard, Background, Border, Color, Element, Fill, Subscription, Task, Theme};
 use iced_aw::ContextMenu;
 use std::sync::Arc;
 
@@ -1889,29 +1889,10 @@ bg={bg_ms:.1}ms n={view_count}"
             viewport_stack = viewport_stack.push(tab.graph.view(sections));
         }
 
-        // Docked side panels (Properties, block palette, future palettes) live
+        // Docked pallets: each edge's icon strip and shown group (see
-        // in an ordered vertical stack on the left/right edge of the drawing
+        // `app::dock`).
-        // view. Auto-collapsing (pinned) panels that aren't being hovered
+        let left_edge = self.build_edge_stack(crate::app::config::DockSide::Left, tab);
-        // reduce to a rail sharing 1/N of the edge column's height; the
+        let right_edge = self.build_edge_stack(crate::app::config::DockSide::Right, tab);
-        // hovered or unpinned panel expands to the full column height on top.
-        // Single source of truth with dock_visible_len (#57): one new panel
-        // updated in only one place used to break drag math vs rendering.
-        let visible_panel = |id: crate::ui::dock::PanelId| -> bool { self.dock_panel_visible(id) };
-        let edge_stack = |side: crate::app::config::DockSide| -> Option<Element<'_, Message>> {
-            let ids: Vec<crate::ui::dock::PanelId> = match side {
-                crate::app::config::DockSide::Left => self.dock.left.clone(),
-                crate::app::config::DockSide::Right => self.dock.right.clone(),
-            }
-            .into_iter()
-            .filter(|id| visible_panel(*id))
-            .collect();
-            if ids.is_empty() {
-                return None;
-            }
-            Some(self.build_edge_stack(side, &ids, tab))
-        };
-        let left_edge = edge_stack(crate::app::config::DockSide::Left);
-        let right_edge = edge_stack(crate::app::config::DockSide::Right);
 
         // Command-line sits as a bottom-centre overlay on top of the
         // viewport stack rather than as a separate row in the main
@@ -1957,158 +1938,7 @@ bg={bg_ms:.1}ms n={view_count}"
         }
         let workspace: Element<'_, Message> = row(parts).width(Fill).height(Fill).into();
 
-        let any_dragging = self.dock_dragging.is_some();
+        let workspace = self.dock_overlay(workspace, tab);
-        let any_resizing =
-            self.dock_resizing.is_some() || self.xref_col_drag.is_some() || self.xref_split_drag;
-        let workspace = if any_dragging {
-            let id = self.dock_dragging.expect("guarded by any_dragging");
-            let side = self.dock_drag_target.map(|(s, _)| s).unwrap_or(
-                self.dock
-                    .location(id)
-                    .map(|(s, _)| s)
-                    .unwrap_or(crate::app::config::DockSide::Right),
-            );
-            // Dropping onto an edge joins that edge's stack, whose column is as
-            // wide as its widest currently-shown panel (the dragged panel
-            // included). Hidden (closed) panels don't render, so they can't
-            // widen the column being previewed.
-            let preview_width = {
-                let mut widths: Vec<f32> = match side {
-                    crate::app::config::DockSide::Left => &self.dock.left,
-                    crate::app::config::DockSide::Right => &self.dock.right,
-                }
-                .iter()
-                .copied()
-                .filter(|&pid| self.dock_panel_visible(pid))
-                .map(|pid| self.dock.width(pid, self.win_size.0))
-                .collect();
-                widths.push(self.dock.width(id, self.win_size.0));
-                widths.into_iter().fold(0.0, f32::max)
-            };
-            // Faint tint over the whole edge column so the target edge reads
-            // even before the panel-sized ghost snaps to a slot.
-            let edge_tint = container(Space::new())
-                .width(Length::Fixed(preview_width))
-                .height(Fill)
-                .style(|theme: &Theme| {
-                    let palette = theme.palette();
-                    container::Style {
-                        background: Some(Background::Color(
-                            palette.primary.weak.color.scale_alpha(0.35),
-                        )),
-                        ..Default::default()
-                    }
-                });
-            // The ghost is the dragged panel at its real size: its own saved
-            // width and its 1/N share of the edge (N = number of panels shown
-            // on the edge after the drop), with a header naming which panel is
-            // being moved. Only visibly-docked panels share the column height:
-            // a hidden (closed) panel keeps its stack slot but no screen space,
-            // so it must not split the preview.
-            let was_here = self.dock.location(id).map(|(s, _)| s) == Some(side);
-            let visible = self.dock_visible_len(side);
-            let final_count = if was_here {
-                std::cmp::max(visible, 1)
-            } else {
-                visible + 1
-            };
-            let edge_h = tab.scene.selection.borrow().view.vp_size.1;
-            let slot_h = edge_h / final_count as f32;
-            let index = self.dock_drag_target.map(|(_, i)| i).unwrap_or(0);
-            let slot = index.min(final_count.saturating_sub(1));
-            let ghost_top = slot as f32 * slot_h;
-            let ghost_header = container(text(id.title()).size(12))
-                .width(Fill)
-                .padding(iced::Padding {
-                    top: 5.0,
-                    right: 8.0,
-                    bottom: 5.0,
-                    left: 8.0,
-                })
-                .style(|theme: &Theme| {
-                    let palette = theme.palette();
-                    container::Style {
-                        background: Some(Background::Color(palette.primary.base.color)),
-                        text_color: Some(palette.primary.base.text),
-                        ..Default::default()
-                    }
-                });
-            let ghost_panel = container(column![ghost_header, Space::new()])
-                .width(Length::Fixed(self.dock.width(id, self.win_size.0)))
-                .height(Length::Fixed(slot_h))
-                .style(|theme: &Theme| {
-                    let palette = theme.palette();
-                    container::Style {
-                        background: Some(Background::Color(palette.background.base.color)),
-                        border: Border {
-                            color: palette.primary.base.color,
-                            width: 2.0,
-                            radius: 0.0.into(),
-                        },
-                        ..Default::default()
-                    }
-                });
-            // Position the ghost at its drop slot, flush against the edge.
-            let ghost = container(ghost_panel)
-                .width(Fill)
-                .height(Fill)
-                .align_x(match side {
-                    crate::app::config::DockSide::Left => iced::alignment::Horizontal::Left,
-                    crate::app::config::DockSide::Right => iced::alignment::Horizontal::Right,
-                })
-                .align_y(iced::alignment::Vertical::Top)
-                .padding(iced::Padding {
-                    top: ghost_top,
-                    right: 0.0,
-                    bottom: 0.0,
-                    left: 0.0,
-                });
-            // Thin line across the column at the drop slot's top boundary.
-            let drop_line = container(
-                container(Space::new())
-                    .width(Fill)
-                    .height(Length::Fixed(3.0))
-                    .style(|theme: &Theme| container::Style {
-                        background: Some(Background::Color(theme.palette().primary.base.color)),
-                        ..Default::default()
-                    }),
-            )
-            .width(Fill)
-            .height(Fill)
-            .align_y(iced::alignment::Vertical::Top)
-            .padding(iced::Padding {
-                top: ghost_top,
-                right: 0.0,
-                bottom: 0.0,
-                left: 0.0,
-            });
-            let preview = iced::widget::stack![edge_tint, ghost, drop_line]
-                .width(Length::Fixed(preview_width))
-                .height(Fill);
-            let preview = container(preview)
-                .width(Fill)
-                .height(Fill)
-                .align_x(match side {
-                    crate::app::config::DockSide::Left => iced::alignment::Horizontal::Left,
-                    crate::app::config::DockSide::Right => iced::alignment::Horizontal::Right,
-                });
-            stack![workspace, preview].width(Fill).height(Fill).into()
-        } else {
-            workspace
-        };
-        let workspace: Element<'_, Message> = if any_dragging || any_resizing {
-            mouse_area(workspace)
-                .on_move(move |p| Message::Dock(crate::ui::dock::DockMsg::DragMove(p)))
-                .on_release(Message::Dock(crate::ui::dock::DockMsg::DragRelease))
-                .interaction(if any_resizing {
-                    iced::mouse::Interaction::ResizingHorizontally
-                } else {
-                    iced::mouse::Interaction::Grabbing
-                })
-                .into()
-        } else {
-            workspace
-        };
         let command_line = self.command_line.view(
             allow_autocomplete,
             dyn_capturing,
@@ -2900,198 +2730,6 @@ impl OpenCADStudio {
     pub(super) fn unfocus_widgets(&self) -> Task<Message> {
         iced::advanced::widget::operate(iced::advanced::widget::operation::focusable::unfocus())
     }
-
-    /// Build one edge: a narrow tab strip at the very edge plus the expanded
-    /// panels sliding out beside it. Auto-collapsing (pinned) panels are always
-    /// visible as equal-height 1/N tabs in the strip (via `Fill` distribution);
-    /// hovering a tab raises its panel to full column height beside the strip,
-    /// so switching between stacked panels is a direct tab-to-tab hover with no
-    /// width-jumping collapse dance. Unpinned panels are always expanded. The
-    /// whole edge is one hover region: leaving it collapses any auto-collapsing
-    /// panel, but moving between the tabs and the expanded panel does not.
-    fn build_edge_stack<'a>(
-        &'a self,
-        side: crate::app::config::DockSide,
-        ids: &[crate::ui::dock::PanelId],
-        tab: &'a DocumentTab,
-    ) -> Element<'a, Message> {
-        let pinned: Vec<crate::ui::dock::PanelId> = ids
-            .iter()
-            .copied()
-            .filter(|id| self.dock.auto_collapse(*id))
-            .collect();
-        // Expanded = unpinned panels (always open) in stack order, then the
-        // hovered auto-collapsing one last so it floats on top.
-        let mut expanded: Vec<crate::ui::dock::PanelId> = ids
-            .iter()
-            .copied()
-            .filter(|id| !self.dock.auto_collapse(*id))
-            .collect();
-        if let Some(id) = self.dock_expanded {
-            if ids.contains(&id) && self.dock.auto_collapse(id) {
-                expanded.push(id);
-            }
-        }
-        // Each expanded panel renders at its own saved width; the column is as
-        // wide as the widest one currently showing.
-        let col_w = expanded
-            .iter()
-            .map(|id| self.dock.width(*id, self.win_size.0))
-            .fold(0.0, f32::max);
-
-        let tab_strip = (!pinned.is_empty()).then(|| {
-            let tabs: Vec<Element<'_, Message>> = pinned
-                .iter()
-                .map(|id| {
-                    self.rail_slice(
-                        *id,
-                        side,
-                        self.dock_expanded == Some(*id),
-                        self.dock_dragging == Some(*id),
-                    )
-                })
-                .collect();
-            column(tabs).width(DOCK_RAIL_W).height(Fill).into()
-        });
-        let expanded_stack = (!expanded.is_empty()).then(|| {
-            // Multiple simultaneously-expanded panels (e.g. two unpinned panels
-            // on the same edge) stack one below the other, each taking 1/N of
-            // the column height via equal `Fill` shares — never overlapping.
-            let layers: Vec<Element<'_, Message>> = expanded
-                .iter()
-                .map(|id| self.expanded_panel(*id, side, col_w, tab))
-                .collect();
-            column(layers).height(Fill).into()
-        });
-
-        let mut children: Vec<Element<'_, Message>> = Vec::new();
-        match side {
-            crate::app::config::DockSide::Left => {
-                if let Some(t) = tab_strip {
-                    children.push(t);
-                }
-                if let Some(e) = expanded_stack {
-                    children.push(e);
-                }
-            }
-            crate::app::config::DockSide::Right => {
-                if let Some(e) = expanded_stack {
-                    children.push(e);
-                }
-                if let Some(t) = tab_strip {
-                    children.push(t);
-                }
-            }
-        }
-        mouse_area(row(children).height(Fill))
-            .on_exit(Message::Dock(crate::ui::dock::DockMsg::HoverExit))
-            .into()
-    }
-
-    /// One narrow tab in the edge strip. Equal `Fill` heights across the tabs
-    /// give each 1/N of the strip; hovering or clicking it raises its panel.
-    fn rail_slice(
-        &self,
-        id: crate::ui::dock::PanelId,
-        side: crate::app::config::DockSide,
-        is_active: bool,
-        is_dragging: bool,
-    ) -> Element<'_, Message> {
-        let label = canvas(VBarLabel {
-            text: id.title().to_string(),
-            clockwise: side == crate::app::config::DockSide::Left,
-        })
-        .width(Fill)
-        .height(Fill);
-        let bg = move |theme: &Theme| {
-            let palette = theme.palette();
-            if is_active {
-                palette.primary.weak.color
-            } else if is_dragging {
-                palette.primary.weak.color.scale_alpha(0.55)
-            } else {
-                palette.background.base.color
-            }
-        };
-        let tab = container(label)
-            .width(Length::Fixed(DOCK_RAIL_W))
-            .height(Fill)
-            .style(move |theme: &Theme| container::Style {
-                background: Some(Background::Color(bg(theme))),
-                border: Border {
-                    color: if is_active {
-                        theme.palette().primary.base.color
-                    } else {
-                        theme.palette().background.neutral.color
-                    },
-                    width: 1.0,
-                    radius: 0.0.into(),
-                },
-                ..Default::default()
-            });
-        mouse_area(tab)
-            .interaction(iced::mouse::Interaction::Pointer)
-            .on_press(Message::Dock(crate::ui::dock::DockMsg::DockGrab(id)))
-            .on_enter(Message::Dock(crate::ui::dock::DockMsg::Hover(id)))
-            .into()
-    }
-
-    /// A panel expanded to the full edge column: the panel body plus a
-    /// grabbable divider against the viewport. Hovering is handled by the
-    /// enclosing edge region (see `build_edge_stack`), so the body stays fully
-    /// interactive without fighting the region's hover tracking.
-    fn expanded_panel<'a>(
-        &'a self,
-        id: crate::ui::dock::PanelId,
-        side: crate::app::config::DockSide,
-        width: f32,
-        tab: &'a DocumentTab,
-    ) -> Element<'a, Message> {
-        let auto_collapse = self.dock.auto_collapse(id);
-        let panel: Element<'_, Message> = match id {
-            crate::ui::dock::PanelId::Properties => tab.properties.view(width, auto_collapse),
-            crate::ui::dock::PanelId::BlockPalette => {
-                crate::ui::window::block_palette::view(&self.block_palette, width, auto_collapse)
-            }
-            crate::ui::dock::PanelId::ExternalReferences => {
-                self.xref_manager
-                    .view(width, auto_collapse, tab.xref_missing, &tab.scene.document)
-            }
-            crate::ui::dock::PanelId::Browser => crate::ui::window::browser::view(
-                &tab.scene.document,
-                tab.sketch_session
-                    .as_ref()
-                    .map(|session| session.name.as_str()),
-                width,
-                auto_collapse,
-            ),
-            crate::ui::dock::PanelId::NodeGraph => tab.graph.panel(width, auto_collapse),
-            crate::ui::dock::PanelId::Count => crate::ui::window::count_palette::view(
-                &self.count_palette,
-                tab.count.as_ref(),
-                &tab.scene.document,
-                tab.id,
-                tab.scene.geometry_epoch,
-                width,
-                auto_collapse,
-            ),
-            crate::ui::dock::PanelId::PointCloudManager => crate::ui::window::pc_manager::view(
-                &self.pc_manager,
-                &tab.scene.document,
-                &tab.scene.selected_handles_in_order(),
-                width,
-                auto_collapse,
-            ),
-            crate::ui::dock::PanelId::SheetSetManager => {
-                crate::ui::window::sheet_set::view(&self.sheet_set, width, auto_collapse)
-            }
-        };
-        let divider = dock_divider(id);
-        match side {
-            crate::app::config::DockSide::Left => row![panel, divider].height(Fill).into(),
-            crate::app::config::DockSide::Right => row![divider, panel].height(Fill).into(),
-        }
-    }
 }
 
 // ── Document tab bar ───────────────────────────────────────────────────────
@@ -3420,68 +3058,6 @@ fn pane_mouse_area<'a>(idx: usize) -> Element<'a, Message> {
         .into()
 }
 
-/// Canvas that draws a label rotated 90° (for a collapsed panel's bar).
-struct VBarLabel {
-    text: String,
-    clockwise: bool,
-}
-
-impl canvas::Program<Message> for VBarLabel {
-    type State = ();
-
-    fn draw(
-        &self,
-        _state: &(),
-        renderer: &iced::Renderer,
-        theme: &Theme,
-        bounds: iced::Rectangle,
-        _cursor: iced::advanced::mouse::Cursor,
-    ) -> Vec<canvas::Geometry> {
-        let mut frame = canvas::Frame::new(renderer, bounds.size());
-        frame.with_save(|frame| {
-            frame.translate(iced::Vector::new(bounds.width / 2.0, bounds.height / 2.0));
-            frame.rotate(iced::Radians(if self.clockwise {
-                std::f32::consts::FRAC_PI_2
-            } else {
-                -std::f32::consts::FRAC_PI_2
-            }));
-            frame.fill_text(canvas::Text {
-                content: self.text.clone(),
-                position: iced::Point::ORIGIN,
-                color: theme.palette().background.base.text.scale_alpha(0.72),
-                size: iced::Pixels(13.0),
-                align_x: iced::advanced::text::Alignment::Center,
-                align_y: iced::alignment::Vertical::Center,
-                shaping: iced::advanced::text::Shaping::Advanced,
-                ..Default::default()
-            });
-        });
-        vec![frame.into_geometry()]
-    }
-}
-
-/// Width of a collapsed (auto-collapsing) panel's tab in the edge strip.
-const DOCK_RAIL_W: f32 = 28.0;
-
-/// Grabbable separator for a docked panel managed by the general dock. Same
-/// visual as the previous per-panel divider but emits generic dock messages.
-fn dock_divider(id: crate::ui::dock::PanelId) -> Element<'static, Message> {
-    let line = container(Space::new())
-        .width(Length::Fixed(5.0))
-        .height(Fill)
-        .style(|theme: &Theme| container::Style {
-            background: Some(Background::Color(theme.palette().background.neutral.color)),
-            ..Default::default()
-        });
-    let grab = Message::Dock(crate::ui::dock::DockMsg::ResizeGrab(id));
-    let reset = Message::Dock(crate::ui::dock::DockMsg::WidthReset(id));
-    mouse_area(line)
-        .on_press(grab)
-        .on_double_click(reset)
-        .interaction(iced::mouse::Interaction::ResizingHorizontally)
-        .into()
-}
-
 const START_ACTION_RADIUS: f32 = 6.0;
 
 fn start_action_shape(mut style: button::Style) -> button::Style {

src/app/view/modal.rs

@@ -19,7 +19,6 @@ impl OpenCADStudio {
             Some(K::PluginManager) => crate::tr!("modal", "plugin-manager"),
             Some(K::UpdateNotice) => crate::tr!("modal", "update-available"),
             Some(K::DonationPrompt) => crate::tr!("donation", "title"),
-            Some(K::Layers) => crate::tr!("modal", "layer-manager"),
             Some(K::LayerStateManager) => crate::tr!("modal", "layer-state-manager"),
             Some(K::LayerTranslator) => crate::t!("Layer Translator").into_owned(),
             Some(K::DrawingUnits) => crate::t!("Drawing Units").into_owned(),
@@ -465,12 +464,6 @@ impl OpenCADStudio {
                     crate::ui::window::update_notice::view_window(latest, body, flow)
                 })
             }
-            super::super::ModalKind::Layers => {
-                let tab = &self.tabs[self.active_tab];
-                sized_flow(ex, 900, 360, |flow| {
-                    tab.layers.view_window(self.layer_name_col_w, flow)
-                })
-            }
             super::super::ModalKind::LayerTranslator => {
                 use crate::modules::draw::layers::laytrans;
                 let i = self.active_tab;

src/locale_catalog.rs

@@ -5765,6 +5765,13 @@ pub(super) fn message_attribute(source: &str) -> Option<(&'static str, &'static
         "Invalid count area boundary object. Select a closed polyline consisting of line segments and does not intersect itself." => Some(("count-feature", "invalid-boundary")),
         "Block \"{part}\" cannot be found." => Some(("count-feature", "block-not-found")),
         "Invalid point." => Some(("count-feature", "invalid-point")),
+        "Auto-hide" => Some(("dock", "auto-hide")),
+        "Allow docking" => Some(("dock", "allow-docking")),
+        "Dock left" => Some(("dock", "dock-left")),
+        "Dock right" => Some(("dock", "dock-right")),
+        "New group" => Some(("dock", "new-group")),
+        "Browser" => Some(("dock", "browser")),
+        "Node Graph" => Some(("dock", "node-graph")),
         _ => None,
     }
 }

src/modules/draw/layers/panel.rs

@@ -1,4 +1,4 @@
-// Layers panel toggle — ribbon definition.
+// Layer Manager pallet — ribbon definition.
 
 use crate::modules::{IconKind, ModuleEvent, ToolDef};
 
@@ -7,6 +7,8 @@ pub fn tool() -> ToolDef {
         id: "LAYERS",
         label: "Layers",
         icon: IconKind::Svg(include_bytes!("../../../../assets/icons/layers/panel.svg")),
-        event: ModuleEvent::ToggleLayers,
+        // A command like the Blocks palette's: it opens the pallet, and the
+        // ribbon drops the button's highlight once it has run.
+        event: ModuleEvent::Command("LAYERS".to_string()),
     }
 }

src/ui/icons.rs

@@ -72,7 +72,11 @@ pub static COPY: &[u8] = include_bytes!("../../assets/icons/ui/copy.svg");
 pub static MENU: &[u8] = include_bytes!("../../assets/icons/ui/menu.svg");
 pub static MOVE: &[u8] = include_bytes!("../../assets/icons/ui/move.svg");
 pub static RESIZE: &[u8] = include_bytes!("../../assets/icons/ui/resize.svg");
+/// `RESIZE` mirrored for a bottom-left corner grip.
+pub static RESIZE_LEFT: &[u8] = include_bytes!("../../assets/icons/ui/resize_left.svg");
 pub static PIN: &[u8] = include_bytes!("../../assets/icons/ui/pin.svg");
+/// `PIN` tilted 30°: the pin while auto-hide is on.
+pub static PIN_ACTIVE: &[u8] = include_bytes!("../../assets/icons/ui/pin_active.svg");
 pub static SPLIT_V: &[u8] = include_bytes!("../../assets/icons/ui/split_v.svg");
 pub static SPLIT_H: &[u8] = include_bytes!("../../assets/icons/ui/split_h.svg");
 pub static GRID: &[u8] = include_bytes!("../../assets/icons/ui/grid.svg");

src/ui/node_graph.rs

@@ -658,7 +658,7 @@ impl Graph {
     /// The node library as a docked panel: title bar, a search box with the
     /// graph's New / Open / Save beside it, then the categories. Entries are
     /// clicked or dragged onto the canvas.
-    pub fn panel(&self, width: f32, auto_collapse: bool) -> Element<'_, Message> {
+    pub fn panel(&self, width: f32, chrome: crate::ui::dock::Chrome) -> Element<'_, Message> {
         use crate::ui::dock::{self, PanelId};
         let tool = |icon: &'static [u8], tip: &str, message: GraphMsg| {
             dock::tool_button(
@@ -740,16 +740,8 @@ impl Graph {
         .height(Length::Fill);
 
         dock::frame(
-            column![
+            dock::title_bar(PanelId::NodeGraph, t!("Node Graph").into_owned(), chrome),
-                dock::title_bar(
+            column![toolbar, body].spacing(6),
-                    PanelId::NodeGraph,
-                    t!("Node Graph").into_owned(),
-                    auto_collapse
-                ),
-                toolbar,
-                body
-            ]
-            .spacing(6),
             width,
         )
     }

src/ui/properties.rs

@@ -544,14 +544,11 @@ impl PropertiesPanel {
             .unwrap_or_default()
     }
 
-    pub fn view(&self, width: f32, auto_collapse: bool) -> Element<'_, Message> {
+    pub fn view(&self, width: f32, chrome: crate::ui::dock::Chrome) -> Element<'_, Message> {
         use crate::ui::dock::PanelId;
         // ── Header ──────────────────────────────────────────────────────────
-        let header = crate::ui::dock::title_bar(
+        let header =
-            PanelId::Properties,
+            crate::ui::dock::title_bar(PanelId::Properties, t!("Properties").into_owned(), chrome);
-            t!("Properties").into_owned(),
-            auto_collapse,
-        );
 
         // ── Title bar (entity type / "No Selection") ─────────────────────
         let title_content: Element<'_, Message> = if self.selection_groups.is_empty() {

src/ui/window/block_palette.rs

@@ -800,11 +800,15 @@ fn options_card<'a>(palette: &'a BlockPalette) -> Element<'a, Message> {
 }
 
 /// Build the docked panel element from the palette state.
-pub fn view(palette: &BlockPalette, width: f32, auto_collapse: bool) -> Element<'_, Message> {
+pub fn view(
+    palette: &BlockPalette,
+    width: f32,
+    chrome: crate::ui::dock::Chrome,
+) -> Element<'_, Message> {
     let title_bar = crate::ui::dock::title_bar(
         PanelId::BlockPalette,
         crate::t!("Blocks").into_owned(),
-        auto_collapse,
+        chrome,
     );
 
     let tabs = {
@@ -991,7 +995,8 @@ pub fn view(palette: &BlockPalette, width: f32, auto_collapse: bool) -> Element<
     };
 
     crate::ui::dock::frame(
-        column![title_bar, top, body, options_card(palette)].spacing(6),
+        title_bar,
+        column![top, body, options_card(palette)].spacing(6),
         width,
     )
 }

src/ui/window/browser.rs

@@ -100,13 +100,10 @@ pub fn view<'a>(
     document: &'a CadDocument,
     open_sketch: Option<&'a str>,
     width: f32,
-    auto_collapse: bool,
+    chrome: crate::ui::dock::Chrome,
 ) -> Element<'a, Message> {
-    let title_bar = crate::ui::dock::title_bar(
+    let title_bar =
-        PanelId::Browser,
+        crate::ui::dock::title_bar(PanelId::Browser, crate::t!("Browser").into_owned(), chrome);
-        crate::t!("Browser").into_owned(),
-        auto_collapse,
-    );
 
     let mut tree = column![].spacing(1);
 
@@ -151,5 +148,5 @@ pub fn view<'a>(
     .width(Fill)
     .height(Fill);
 
-    crate::ui::dock::frame(column![title_bar, body].spacing(6), width)
+    crate::ui::dock::frame(title_bar, column![body].spacing(6), width)
 }

src/ui/window/count_palette.rs

@@ -660,13 +660,10 @@ pub fn view<'a>(
     doc_id: u64,
     epoch: u64,
     width: f32,
-    auto_collapse: bool,
+    chrome: crate::ui::dock::Chrome,
 ) -> Element<'a, Message> {
-    let title_bar = crate::ui::dock::title_bar(
+    let title_bar =
-        PanelId::Count,
+        crate::ui::dock::title_bar(PanelId::Count, crate::t!("Count").into_owned(), chrome);
-        crate::t!("Count").into_owned(),
-        auto_collapse,
-    );
     let body = match mode {
         Some(mode) if mode.target.is_some() => mode_view(palette, mode, doc),
         _ => {
@@ -685,7 +682,7 @@ pub fn view<'a>(
             list_view(palette, &instances)
         }
     };
-    crate::ui::dock::frame(column![title_bar, body].spacing(6), width)
+    crate::ui::dock::frame(title_bar, column![body].spacing(6), width)
 }
 
 fn bar_button<'a>(

src/ui/window/layers.rs

@@ -337,20 +337,40 @@ impl LayerPanel {
             .collect()
     }
 
-    /// Render the layer panel as the full content of its own OS window.
+    /// The Layer Manager as a dock pallet: its title bar, the toolbar across
-    pub fn view_window(
+    /// the pallet (search box on the right), then the table, at least as wide
+    /// as the pallet and scrolling sideways when the pallet is narrower.
+    pub fn view_panel(
         &self,
         name_col_w: f32,
-        sizing: crate::ui::modal::ModalSizing,
+        width: f32,
+        chrome: crate::ui::dock::Chrome,
     ) -> Element<'_, Message> {
-        self.view_content(name_col_w, sizing)
+        use crate::ui::dock::PanelId;
+        let title_bar = crate::ui::dock::title_bar(
+            PanelId::Layers,
+            crate::tr!("modal", "layer-manager"),
+            chrome,
+        );
+        // Inside the pallet's 1 px border on either side.
+        let body = self.view_content(name_col_w, (width - 2.0).max(0.0));
+        container(column![title_bar, body])
+            .width(Length::Fixed(width))
+            .height(Length::Fill)
+            .style(|theme: &Theme| container::Style {
+                background: Some(Background::Color(theme.palette().background.base.color)),
+                border: Border {
+                    color: theme.palette().background.neutral.color,
+                    width: 1.0,
+                    radius: 0.0.into(),
+                },
+                ..Default::default()
+            })
+            .into()
     }
 
-    fn view_content(
+    /// Toolbar and table for a pallet `inner_w` wide.
-        &self,
+    fn view_content(&self, name_col_w: f32, inner_w: f32) -> Element<'_, Message> {
-        name_col_w: f32,
-        sizing: crate::ui::modal::ModalSizing,
-    ) -> Element<'_, Message> {
         let has_sel = self.selected.is_some();
         let sel_is_zero = self
             .selected
@@ -377,7 +397,7 @@ impl LayerPanel {
                     Message::LayerSetCurrent,
                     can_set_current,
                 ),
-                iced::widget::Space::new().width(sizing.width),
+                iced::widget::Space::new().width(Length::Fill),
                 // Search box: filters rows by name as the user types (#343).
                 text_input(t!("Search…").as_ref(), &self.filter)
                     .on_input(Message::LayerManagerFilterChanged)
@@ -393,7 +413,7 @@ impl LayerPanel {
             background: Some(Background::Color(theme.palette().background.weak.color)),
             ..Default::default()
         })
-        .width(sizing.width)
+        .width(Length::Fill)
         .padding([4, 8]);
 
         // ── Column header ─────────────────────────────────────────────────
@@ -473,7 +493,6 @@ impl LayerPanel {
             ),
         ]
         .spacing(4)
-        .width(sizing.width)
         .align_y(iced::Center);
 
         for vp in &self.vp_cols {
@@ -499,7 +518,7 @@ impl LayerPanel {
                 }
             })
             .padding([4, 8])
-            .width(sizing.width);
+            .width(Length::Fill);
 
         // ── Layer rows ────────────────────────────────────────────────────
         let mut rows_col = column![].spacing(0);
@@ -536,17 +555,28 @@ impl LayerPanel {
 
         let table = scrollable(rows_col)
             .id(iced::advanced::widget::Id::new(LAYER_TABLE_SCROLL_ID))
-            .height(sizing.height.min(240.0));
+            .width(Length::Fill)
+            .height(Length::Fill);
 
-        // ── Full-window frame ─────────────────────────────────────────────
+        // The header and table stretch to the wider of their columns and the
-        container(column![toolbar, col_header, table].spacing(0))
+        // pallet (the zero-height spacer), so the header's grey band and
-            .style(|theme: &Theme| container::Style {
+        // borders always run to the pallet's edge; a narrower pallet scrolls
-                background: Some(Background::Color(theme.palette().background.base.color)),
+        // the table sideways while the toolbar stays put.
-                ..Default::default()
+        let grid = column![
-            })
+            col_header,
-            .width(sizing.width)
+            table,
-            .height(sizing.height)
+            iced::widget::Space::new()
-            .into()
+                .width(Length::Fixed(inner_w))
+                .height(0),
+        ]
+        .height(Length::Fill);
+        let grid = scrollable(grid)
+            .direction(iced::widget::scrollable::Direction::Horizontal(
+                iced::widget::scrollable::Scrollbar::new(),
+            ))
+            .width(Length::Fill)
+            .height(Length::Fill);
+        column![toolbar, grid].height(Length::Fill).into()
     }
 }
 

src/ui/window/pc_manager.rs

@@ -277,12 +277,12 @@ pub fn view<'a>(
     document: &'a CadDocument,
     selected: &[Handle],
     width: f32,
-    auto_collapse: bool,
+    chrome: crate::ui::dock::Chrome,
 ) -> Element<'a, Message> {
     let title_bar = crate::ui::dock::title_bar(
         PanelId::PointCloudManager,
         crate::t!("Point Cloud Manager").into_owned(),
-        auto_collapse,
+        chrome,
     );
     let query = state.search.trim().to_lowercase();
     let matches = |label: &str| query.is_empty() || label.to_lowercase().contains(&query);
@@ -416,5 +416,5 @@ pub fn view<'a>(
         .padding([4, 8])
         .size(12);
 
-    crate::ui::dock::frame(column![title_bar, card, search].spacing(6), width)
+    crate::ui::dock::frame(title_bar, column![card, search].spacing(6), width)
 }

src/ui/window/sheet_set.rs

@@ -1153,12 +1153,12 @@ fn heading(label: &str) -> Element<'static, Message> {
 pub fn view<'a>(
     state: &'a SheetSetManager,
     width: f32,
-    auto_collapse: bool,
+    chrome: crate::ui::dock::Chrome,
 ) -> Element<'a, Message> {
     let title_bar = crate::ui::dock::title_bar(
         PanelId::SheetSetManager,
         t!("Sheet Set Manager").into_owned(),
-        auto_collapse,
+        chrome,
     );
     let mut picks: Vec<Pick> = state
         .sets
@@ -1305,7 +1305,8 @@ pub fn view<'a>(
         .size(10)
         .style(muted_style);
     crate::ui::dock::frame(
-        column![title_bar, combo, tabs, card, hint].spacing(6),
+        title_bar,
+        column![combo, tabs, card, hint].spacing(6),
         width,
     )
 }

src/ui/window/xref_manager.rs

@@ -590,7 +590,7 @@ impl XrefManagerPanel {
     pub fn view<'a>(
         &'a self,
         width: f32,
-        auto_collapse: bool,
+        chrome: crate::ui::dock::Chrome,
         missing: usize,
         doc: &'a CadDocument,
     ) -> Element<'a, Message> {
@@ -602,7 +602,7 @@ impl XrefManagerPanel {
                 crate::t!("External References").as_ref(),
                 self.entries.len()
             ),
-            auto_collapse,
+            chrome,
         );
         // Table content width: column widths plus gutters, stretched to the
         // dock when wider so rows fill the panel; narrower docks sidescroll.