bar-shell: prevent bar crash on rapid visibility toggle and convert IPCService to singleton

Modules/MainScreen/AllScreens.qml

@@ -54,9 +54,12 @@ Variants {
     }
 
     // Bar content in separate windows to prevent fullscreen redraws
+    // Note: Window stays alive when bar is hidden (visible=false) to avoid
+    // rapid Wayland surface destruction/creation that can crash compositors.
+    // Content is debounce-unloaded inside BarContentWindow.
     Loader {
       active: {
-        if (!parent.windowLoaded || !parent.shouldBeActive || !BarService.effectivelyVisible)
+        if (!parent.windowLoaded || !parent.shouldBeActive)
           return false;
 
         // Check if bar is configured for this screen
@@ -130,7 +133,8 @@ Variants {
     }
 
     // PopupMenuWindow - reusable popup window for both tray menus and context menus
-    // Active when bar is visible on this screen, OR when desktop widgets edit mode is active
+    // Stays alive when bar is hidden to avoid Wayland surface churn crashes.
+    // PopupMenuWindow manages its own visibility internally.
     Loader {
       active: {
         // Desktop widgets edit mode needs popup window on ALL screens
@@ -139,7 +143,7 @@ Variants {
         }
 
         // Normal bar-based condition
-        if (!parent.windowLoaded || !parent.shouldBeActive || !BarService.effectivelyVisible)
+        if (!parent.windowLoaded || !parent.shouldBeActive)
           return false;
 
         // Check if bar is configured for this screen

Modules/MainScreen/BarContentWindow.qml

@@ -20,8 +20,8 @@ PanelWindow {
   // Note: screen property is inherited from PanelWindow and should be set by parent
   color: "transparent" // Transparent - background is in MainScreen below
 
-  // Make window pass-through when content is unloaded
-  visible: contentLoaded
+  // Make window pass-through when content is unloaded or bar is hidden via IPC
+  visible: contentLoaded && BarService.effectivelyVisible
 
   Component.onCompleted: {
     Logger.d("BarContentWindow", "Bar content window created for screen:", barWindow.screen?.name);
@@ -169,10 +169,42 @@ PanelWindow {
     } else {
       // Load immediately when showing
       unloadTimer.stop();
+      deferredUnloadTimer.stop();
       contentLoaded = true;
     }
   }
 
+  // Debounced content unload when bar visibility is toggled.
+  // Rapid toggles keep widgets alive; content is only unloaded after the bar
+  // has been continuously hidden for the debounce period.
+  Timer {
+    id: deferredUnloadTimer
+    interval: 1000
+    onTriggered: {
+      if (!BarService.effectivelyVisible) {
+        barWindow.barHovered = false;
+        barWindow.contentLoaded = false;
+        Logger.d("BarContentWindow", "Debounced content unload for screen:", barWindow.screen?.name);
+      }
+    }
+  }
+
+  Connections {
+    target: BarService
+    function onEffectivelyVisibleChanged() {
+      if (!BarService.effectivelyVisible) {
+        // Bar hidden — start debounced unload
+        deferredUnloadTimer.restart();
+      } else {
+        // Bar shown — cancel pending unload, ensure content is loaded
+        deferredUnloadTimer.stop();
+        if (!barWindow.isHidden) {
+          barWindow.contentLoaded = true;
+        }
+      }
+    }
+  }
+
   // Handle floating margins and framed mode offsets
   margins {
     top: (barPosition === "top") ? barMarginV : (isFramed ? frameThickness : barMarginV)

Modules/MainScreen/PopupMenuWindow.qml

@@ -49,6 +49,10 @@ PanelWindow {
     PanelService.registerPopupMenuWindow(screen, root);
   }
 
+  Component.onDestruction: {
+    PanelService.unregisterPopupMenuWindow(screen);
+  }
+
   // Load TrayMenu as the default content
   Loader {
     id: trayMenuLoader

Services/Control/IPCService.qml

@@ -1,3 +1,5 @@
+pragma Singleton
+
 import QtQuick
 import Quickshell
 import Quickshell.Io
@@ -16,22 +18,27 @@ import qs.Services.System
 import qs.Services.Theming
 import qs.Services.UI
 
-Item {
+Singleton {
   id: root
 
-  // Screen detector passed from shell.qml
-  required property CurrentScreenDetector screenDetector
+  // Screen detector, set via init()
+  property var screenDetector: null
+
+  function init(detector) {
+    root.screenDetector = detector;
+    Logger.i("IPCService", "Service started");
+  }
 
   IpcHandler {
     target: "bar"
     function toggle() {
-      BarService.isVisible = !BarService.isVisible;
+      BarService.toggleVisibility();
     }
     function hideBar() {
-      BarService.isVisible = false;
+      BarService.hide();
     }
     function showBar() {
-      BarService.isVisible = true;
+      BarService.show();
     }
     function setDisplayMode(mode: string) {
       if (mode === "always_visible" || mode === "non_exclusive" || mode === "auto_hide") {

Services/UI/BarService.qml

@@ -86,6 +86,49 @@ Singleton {
     return state ? state.hovered : false;
   }
 
+  // Toggle bar visibility. In auto-hide mode, toggles the auto-hide state
+  // on all screens instead of setting the global isVisible flag.
+  function toggleVisibility() {
+    if (Settings.data.bar.displayMode === "auto_hide") {
+      // Check if any screen is currently visible (not hidden)
+      var anyVisible = false;
+      for (var screenName in screenAutoHideState) {
+        if (!screenAutoHideState[screenName].hidden) {
+          anyVisible = true;
+          break;
+        }
+      }
+      // Toggle all screens
+      for (var screenName in screenAutoHideState) {
+        setScreenHidden(screenName, anyVisible);
+      }
+    } else {
+      isVisible = !isVisible;
+    }
+  }
+
+  // Show bar. In auto-hide mode, un-hides on all screens.
+  function show() {
+    if (Settings.data.bar.displayMode === "auto_hide") {
+      for (var screenName in screenAutoHideState) {
+        setScreenHidden(screenName, false);
+      }
+    } else {
+      isVisible = true;
+    }
+  }
+
+  // Hide bar. In auto-hide mode, hides on all screens.
+  function hide() {
+    if (Settings.data.bar.displayMode === "auto_hide") {
+      for (var screenName in screenAutoHideState) {
+        setScreenHidden(screenName, true);
+      }
+    } else {
+      isVisible = false;
+    }
+  }
+
   Component.onCompleted: {
     Logger.i("BarService", "Service started");
   }

Services/UI/PanelService.qml

@@ -65,6 +65,15 @@ Singleton {
     popupMenuWindowRegistered(screen);
   }
 
+  // Unregister popup menu window for a screen (called on destruction)
+  function unregisterPopupMenuWindow(screen) {
+    if (!screen)
+      return;
+    var key = screen.name;
+    delete popupMenuWindows[key];
+    Logger.d("PanelService", "Unregistered popup menu window for screen:", key);
+  }
+
   // Get popup menu window for a screen
   function getPopupMenuWindow(screen) {
     if (!screen)

shell.qml

@@ -113,6 +113,7 @@ ShellRoot {
           GitHubService.init();
           SupporterService.init();
           CustomButtonIPCService.init();
+          IPCService.init(screenDetector);
         });
 
         delayedInitTimer.running = true;
@@ -145,11 +146,7 @@ ShellRoot {
         id: screenDetector
       }
 
-      // IPCService is treated as a service but it must be in graphics scene.
-      IPCService {
-        id: ipcService
-        screenDetector: screenDetector
-      }
+      // IPCService is a singleton, initialized via init() in deferred services block
 
       // Container for plugins Main.qml instances (must be in graphics scene)
       Item {