gwl: Update instances correctly when the monitor configuration

changes.

- Use muffin's display to get the correct number of monitors - when
  the applet is refreshed, the GdkScreen doesn't have an accurate
  count at that point.
- Don't refresh appLists asynchronously as their apps may have
  disappeared to another instance and are no longer valid for this
  one.
- Make it possible to cancel the attention flash if the item gets
  destroyed before it completes.

ref: #11106

Author: mtwebster

files/usr/share/cinnamon/applets/[email protected]/appGroup.js

@@ -7,6 +7,7 @@ const Tweener = imports.ui.tweener;
 const DND = imports.ui.dnd;
 const Tooltips = imports.ui.tooltips;
 const PopupMenu = imports.ui.popupMenu;
+const Mainloop = imports.mainloop;
 const {SignalManager} = imports.misc.signalManager;
 const {each, findIndex, unref} = imports.misc.util;
 const {createStore} = imports.misc.state;
@@ -97,6 +98,7 @@ class AppGroup {
 
         this.signals = new SignalManager(null);
         this.appKeyTimeout = 0;
+        this.flashTimer = 0;
 
         // TODO: This needs to be in state so it can be updated more reliably.
         this.labelVisiblePref = this.state.settings.titleDisplay !== TitleDisplay.None && this.state.isHorizontal;
@@ -318,15 +320,18 @@ class AppGroup {
         this.actor.remove_style_pseudo_class('active');
         this.actor.add_style_class_name('grouped-window-list-item-demands-attention');
         if (counter < FLASH_MAX_COUNT) {
-            setTimeout(() => {
+            this.flashTimer = Mainloop.timeout_add(FLASH_INTERVAL, () => {
                 if (this.actor && this.actor.has_style_class_name('grouped-window-list-item-demands-attention')) {
                     this.actor.remove_style_class_name('grouped-window-list-item-demands-attention');
                     this.actor.add_style_pseudo_class('active');
                 }
-                setTimeout(() => {
+
+                this.flashTimer = Mainloop.timeout_add(FLASH_INTERVAL, () => {
                     this.flashButton(++counter);
-                }, FLASH_INTERVAL);
-            }, FLASH_INTERVAL);
+                });
+            });
+        } else {
+            this.flashTimer = 0;
         }
     }
 
@@ -1141,6 +1146,11 @@ class AppGroup {
         this.signals.disconnectAllSignals();
         this.groupState.set({willUnmount: true});
 
+        if (this.flashTimer > 0) {
+            Mainloop.source_remove(this.flashTimer);
+            this.flashTimer = 0;
+        }
+
         if (this.rightClickMenu) {
             if (this.rightClickMenu.isOpen) {
                 this.rightClickMenu.close();

files/usr/share/cinnamon/applets/[email protected]/applet.js

@@ -295,7 +295,7 @@ class GroupedWindowListApplet extends Applet.Applet {
         this.signals.connect(global.window_manager, 'switch-workspace', (...args) => this.onSwitchWorkspace(...args));
         this.signals.connect(global.screen, 'workspace-removed', (...args) => this.onWorkspaceRemoved(...args));
         this.signals.connect(global.screen, 'window-monitor-changed', (...args) => this.onWindowMonitorChanged(...args));
-        this.signals.connect(Main.panelManager, 'monitors-changed', (...args) => this.on_applet_instances_changed(...args));
+        this.signals.connect(Main.panelManager, 'monitors-changed', (...args) => this._onMonitorsChanged(...args));
         this.signals.connect(global.screen, 'window-skip-taskbar-changed', (...args) => this.onWindowSkipTaskbarChanged(...args));
         this.signals.connect(global.display, 'window-marked-urgent', (...args) => this.updateAttentionState(...args));
         this.signals.connect(global.display, 'window-demands-attention', (...args) => this.updateAttentionState(...args));
@@ -369,21 +369,29 @@ class GroupedWindowListApplet extends Applet.Applet {
         this.state.set({appletReady: true});
     }
 
-    on_applet_instances_changed(instance) {
+    _updateState(initialUpdate) {
         if (!this.state.appletReady) {
             return;
         }
 
         this.numberOfMonitors = null;
         this.updateMonitorWatchlist();
 
-        if (instance && instance.instance_id === this.instance_id) {
+        if (initialUpdate) {
             this.onSwitchWorkspace();
         } else {
             this.refreshCurrentAppList();
         }
     }
 
+    on_applet_instances_changed(instance) {
+        this._updateState(instance?.instance_id === this.instance_id);
+    }
+
+    _onMonitorsChanged(panelManager) {
+        this._updateState(false);
+    }
+
     on_panel_edit_mode_changed() {
         this.state.set({panelEditMode: !this.state.panelEditMode});
         each(this.appLists, (workspace) => {
@@ -506,7 +514,7 @@ class GroupedWindowListApplet extends Applet.Applet {
 
     updateMonitorWatchlist() {
         if (!this.numberOfMonitors) {
-            this.numberOfMonitors = Gdk.Screen.get_default().get_n_monitors();
+            this.numberOfMonitors = global.display.get_n_monitors();
         }
         let onPrimary = this.panel.monitorIndex === Main.layoutManager.primaryIndex;
         let instances = Main.AppletManager.getRunningInstancesForUuid(this.state.uuid);
@@ -541,7 +549,7 @@ class GroupedWindowListApplet extends Applet.Applet {
 
     refreshCurrentAppList() {
         let appList = this.appLists[this.state.currentWs];
-        if (appList) setTimeout(() => appList.refreshList(), 0);
+        if (appList) appList.refreshList();
     }
 
     refreshAllAppLists() {