UI: preserve window-edge Tools redocking across vertical layouts

crates/ui-egui/src/app.rs

@@ -542,6 +542,9 @@ impl VectorcraftApp {
             // Control bar docked at the bottom has set it to the bar's top.
             widgets::set_menu_floor(&ctx, ctx.content_rect().bottom());
         }
+        if self.ui.toolbar && self.ui.screen_mode < 3 {
+            tools_float::set_window_dock_zone(&ctx, ui.available_rect_before_wrap());
+        }
         if self.ui.toolbar && self.ui.screen_mode < 3 && self.ui.toolbar_pos.is_some() {
             toolbar::show(self, ui);
         } else if !self.ui.toolbar && self.ui.screen_mode < 3 && self.ui.tab_hid.is_none() {

crates/ui-egui/src/panel_docking/tests.rs

@@ -344,6 +344,38 @@ fn tools_follow_left_panels_when_resized_hidden_and_restored() {
     }
 }
 
+#[test]
+fn tools_redock_at_window_edge_above_and_below_canvas() {
+    for above in [true, false] {
+        let mut h = Harness::new();
+        let tabs = |panel: &str| Box::new(Node::Tabs { panels: vec![panel.to_string()], active: 0 });
+        h.app.ui.docking = Some(Layout {
+            root: Some(Node::Split {
+                axis: craft_ui::layout::SplitAxis::Vertical,
+                size: craft_ui::layout::SplitSize::FixedFirst(180.0),
+                first: tabs("layers"),
+                second: Box::new(Node::Split {
+                    axis: craft_ui::layout::SplitAxis::Vertical,
+                    size: craft_ui::layout::SplitSize::FixedSecond(180.0),
+                    first: tabs(CANVAS),
+                    second: tabs("properties"),
+                }),
+            }),
+            floating: vec![],
+        });
+        assert!(valid(&h.layout()));
+        h.app.run("window.panel.float", json!({"panel": "tools", "x": 600, "y": 300})).unwrap();
+        for _ in 0..3 {
+            h.frame(vec![]);
+        }
+        let panel = h.tab(if above { "layers" } else { "properties" }).unwrap();
+        let canvas = h.app.canvas_rect.unwrap();
+        assert!(panel.center().y < canvas.top() || panel.center().y > canvas.bottom());
+        h.drag(pos2(620.0, 307.0), pos2(12.0, panel.center().y));
+        assert_eq!(h.app.ui.toolbar_pos, None, "window-edge drop above canvas: {above}");
+    }
+}
+
 #[test]
 #[ignore = "manual visual check; set LEFT_TOOLS_SCREENSHOTS to an existing harness directory"]
 fn capture_tools_beside_left_panels() {

crates/ui-egui/src/tools_float.rs

@@ -51,15 +51,19 @@ fn window_zone_id() -> Id {
     Id::unique("tools-float-window-zone")
 }
 
-/// Keep the window-edge gesture while also accepting a drop next to panels docked left.
+/// Accept a drop next to panels docked left, independently of the window-edge gesture.
 pub(crate) fn set_dock_zones(ctx: &egui::Context, canvas: Rect, width: f32) {
-    let window = pos2(ctx.content_rect().left(), canvas.top());
     ctx.data_mut(|d| {
         d.insert_temp(tools_zone_id(), Rect::from_min_size(canvas.min, vec2(width, canvas.height())));
-        d.insert_temp(window_zone_id(), Rect::from_min_size(window, vec2(width, canvas.height())));
     });
 }
 
+/// The legacy 48-point window-edge target spans the full layout below the bars, including
+/// panels above and below the canvas. Its width does not follow the toolbar's column count.
+pub(crate) fn set_window_dock_zone(ctx: &egui::Context, window: Rect) {
+    ctx.data_mut(|d| d.insert_temp(window_zone_id(), Rect::from_min_size(window.min, vec2(48.0, window.height()))));
+}
+
 /// `pos` moved so a panel of `size` stays inside `screen` (a position saved on a bigger window).
 pub fn clamp(pos: [f32; 2], size: Vec2, screen: Rect) -> Pos2 {
     let [x, y] = pos;