Onion skin settings: move from floating window to the Info Panel

The standalone egui window didn't fit the UI. Replaced it with a collapsible
"Onion Skin" section at the bottom of the Info Panel (Enabled checkbox + frames
before/after + opacity), available regardless of selection. SharedPaneState carries
a mutable `onion_skin` ref for the controls (distinct from the gated `onion` copy
used by rendering).

lightningbeam-ui/lightningbeam-editor/src/main.rs

@@ -6471,6 +6471,7 @@ impl eframe::App for EditorApp {
                         o.enabled = o.enabled && !self.is_playing;
                         o
                     },
+                    onion_skin: &mut self.onion_skin,
                     tool_icon_cache: &mut self.tool_icon_cache,
                     icon_cache: &mut self.icon_cache,
                     selected_tool: &mut self.selected_tool,
@@ -7032,26 +7033,6 @@ impl eframe::App for EditorApp {
 
         }
 
-        // Onion skin settings window (shown only when onion skinning is enabled)
-        if self.onion_skin.enabled {
-            egui::Window::new("Onion Skin")
-                .resizable(false)
-                .collapsible(true)
-                .anchor(egui::Align2::RIGHT_TOP, [-10.0, 40.0])
-                .show(ctx, |ui| {
-                    ui.label("Onion skin settings");
-                    ui.horizontal(|ui| {
-                        ui.label("Frames before:");
-                        ui.add(egui::DragValue::new(&mut self.onion_skin.frames_before).range(0..=5));
-                    });
-                    ui.horizontal(|ui| {
-                        ui.label("Frames after:");
-                        ui.add(egui::DragValue::new(&mut self.onion_skin.frames_after).range(0..=5));
-                    });
-                    ui.add(egui::Slider::new(&mut self.onion_skin.opacity, 0.0..=1.0).text("Opacity"));
-                });
-        }
-
         // Render custom cursor overlay (on top of everything including debug overlay)
         custom_cursor::render_overlay(ctx, &mut self.cursor_cache);
 

lightningbeam-ui/lightningbeam-editor/src/panes/infopanel.rs

@@ -1035,6 +1035,29 @@ impl InfopanelPane {
             });
     }
 
+    /// Render the onion-skinning view settings (global; not tied to selection).
+    fn render_onion_section(&mut self, ui: &mut Ui, path: &NodePath, shared: &mut SharedPaneState) {
+        egui::CollapsingHeader::new("Onion Skin")
+            .id_salt(("onion", path))
+            .default_open(shared.onion_skin.enabled)
+            .show(ui, |ui| {
+                ui.add_space(4.0);
+                ui.checkbox(&mut shared.onion_skin.enabled, "Enabled");
+                ui.add_enabled_ui(shared.onion_skin.enabled, |ui| {
+                    ui.horizontal(|ui| {
+                        ui.label("Frames before:");
+                        ui.add(DragValue::new(&mut shared.onion_skin.frames_before).range(0..=5));
+                    });
+                    ui.horizontal(|ui| {
+                        ui.label("Frames after:");
+                        ui.add(DragValue::new(&mut shared.onion_skin.frames_after).range(0..=5));
+                    });
+                    ui.add(egui::Slider::new(&mut shared.onion_skin.opacity, 0.0..=1.0).text("Opacity"));
+                });
+                ui.add_space(4.0);
+            });
+    }
+
     /// Render layer info section
     fn render_layer_section(&self, ui: &mut Ui, path: &NodePath, shared: &SharedPaneState, layer_ids: &[Uuid]) {
         let document = shared.action_executor.document();
@@ -1478,6 +1501,12 @@ impl PaneRenderer for InfopanelPane {
                         }
                     }
                 }
+
+                // Onion-skinning view settings — always available, regardless of selection.
+                ui.add_space(8.0);
+                ui.separator();
+                ui.add_space(4.0);
+                self.render_onion_section(ui, path, shared);
             });
     }
 

lightningbeam-ui/lightningbeam-editor/src/panes/mod.rs

@@ -177,6 +177,8 @@ impl OnionSkinSettings {
 pub struct SharedPaneState<'a> {
     /// Effective onion-skin settings (already gated to off during playback by main.rs).
     pub onion: OnionSkinSettings,
+    /// The raw onion-skin settings, mutable — edited by the Info Panel's controls.
+    pub onion_skin: &'a mut OnionSkinSettings,
     pub tool_icon_cache: &'a mut crate::ToolIconCache,
     #[allow(dead_code)] // Used by pane chrome rendering in main.rs
     pub icon_cache: &'a mut crate::IconCache,