Introduce a shell group

src/InternalUtils.vala

@@ -369,5 +369,15 @@ namespace Gala {
                 }
             });
         }
+
+        public static void update_transients_visible (Meta.Window window, bool visible) {
+            window.foreach_transient ((transient) => {
+                var actor = (Meta.WindowActor) transient.get_compositor_private ();
+
+                actor.visible = visible;
+
+                return true;
+            });
+        }
     }
 }

src/ShellClients/HideTracker.vala

@@ -152,7 +152,7 @@ public class Gala.HideTracker : Object {
         });
     }
 
-    private void update_overlap () {
+    public void update_overlap () {
         overlap = false;
         focus_overlap = false;
         focus_maximized_overlap = false;

src/ShellClients/PanelClone.vala

@@ -8,7 +8,7 @@
 public class Gala.PanelClone : Object {
     private const int ANIMATION_DURATION = 250;
 
-    public WindowManager wm { get; construct; }
+    public WindowManagerGala wm { get; construct; }
     public unowned PanelWindow panel { get; construct; }
 
     public Pantheon.Desktop.HideMode hide_mode {
@@ -38,14 +38,16 @@ public class Gala.PanelClone : Object {
 
     private HideTracker? hide_tracker;
 
-    public PanelClone (WindowManager wm, PanelWindow panel) {
+    public PanelClone (WindowManagerGala wm, PanelWindow panel) {
         Object (wm: wm, panel: panel);
     }
 
     construct {
         default_gesture_tracker = new GestureTracker (ANIMATION_DURATION, ANIMATION_DURATION);
 
         actor = (Meta.WindowActor) panel.window.get_compositor_private ();
+        actor.get_parent ().remove_child (actor);
+        wm.shell_group.add_child (actor);
 
         notify["panel-hidden"].connect (() => {
             // When hidden changes schedule an update to make sure it's actually
@@ -55,6 +57,8 @@ public class Gala.PanelClone : Object {
             }
         });
 
+        wm.get_display ().in_fullscreen_changed.connect (check_hide);
+
         Idle.add_once (() => {
             if (hide_mode == NEVER) {
                 show ();
@@ -89,22 +93,38 @@ public class Gala.PanelClone : Object {
             return;
         }
 
-        new GesturePropertyTransition (actor, default_gesture_tracker, "translation-y", null, calculate_y (true)).start (false);
+        InternalUtils.update_transients_visible (panel.window, false);
+
+        new GesturePropertyTransition (
+            actor, default_gesture_tracker, "translation-y", null, calculate_y (true)
+        ).start (false, () => InternalUtils.update_transients_visible (panel.window, !panel_hidden));
 
         default_gesture_tracker.add_success_callback (false, () => panel_hidden = true);
     }
 
     private void show () {
-        if (!panel_hidden || default_gesture_tracker.recognizing) {
+        if (!panel_hidden || default_gesture_tracker.recognizing || wm.get_display ().get_monitor_in_fullscreen (panel.window.get_monitor ())) {
             return;
         }
 
         if (!Meta.Util.is_wayland_compositor ()) {
             Utils.x11_unset_window_pass_through (panel.window);
         }
 
-        new GesturePropertyTransition (actor, default_gesture_tracker, "translation-y", null, calculate_y (false)).start (false);
+        new GesturePropertyTransition (
+            actor, default_gesture_tracker, "translation-y", null, calculate_y (false)
+        ).start (false, () => InternalUtils.update_transients_visible (panel.window, !panel_hidden));
 
         default_gesture_tracker.add_success_callback (false, () => panel_hidden = false);
     }
+
+    private void check_hide () {
+        if (wm.get_display ().get_monitor_in_fullscreen (panel.window.get_monitor ())) {
+            hide ();
+        } else if (hide_mode == NEVER) {
+            show ();
+        } else {
+            hide_tracker.update_overlap ();
+        }
+    }
 }

src/ShellClients/PanelWindow.vala

@@ -8,7 +8,7 @@
 public class Gala.PanelWindow : Object {
     private static HashTable<Meta.Window, Meta.Strut?> window_struts = new HashTable<Meta.Window, Meta.Strut?> (null, null);
 
-    public WindowManager wm { get; construct; }
+    public WindowManagerGala wm { get; construct; }
     public Meta.Window window { get; construct; }
     public Pantheon.Desktop.Anchor anchor { get; construct set; }
 
@@ -19,7 +19,7 @@ public class Gala.PanelWindow : Object {
     private int width = -1;
     private int height = -1;
 
-    public PanelWindow (WindowManager wm, Meta.Window window, Pantheon.Desktop.Anchor anchor) {
+    public PanelWindow (WindowManagerGala wm, Meta.Window window, Pantheon.Desktop.Anchor anchor) {
         Object (wm: wm, window: window, anchor: anchor);
     }
 

src/ShellClients/ShellClientsManager.vala

@@ -8,7 +8,7 @@
 public class Gala.ShellClientsManager : Object {
     private static ShellClientsManager instance;
 
-    public static void init (WindowManager wm) {
+    public static void init (WindowManagerGala wm) {
         if (instance != null) {
             return;
         }
@@ -20,15 +20,15 @@ public class Gala.ShellClientsManager : Object {
         return instance;
     }
 
-    public WindowManager wm { get; construct; }
+    public WindowManagerGala wm { get; construct; }
 
     private NotificationsClient notifications_client;
     private ManagedClient[] protocol_clients = {};
 
     private GLib.HashTable<Meta.Window, PanelWindow> panel_windows = new GLib.HashTable<Meta.Window, PanelWindow> (null, null);
     private GLib.HashTable<Meta.Window, WindowPositioner> positioned_windows = new GLib.HashTable<Meta.Window, WindowPositioner> (null, null);
 
-    private ShellClientsManager (WindowManager wm) {
+    private ShellClientsManager (WindowManagerGala wm) {
         Object (wm: wm);
     }
 

src/Widgets/MultitaskingView.vala

@@ -28,7 +28,7 @@ namespace Gala {
         private GestureTracker multitasking_gesture_tracker;
         private GestureTracker workspace_gesture_tracker;
 
-        public WindowManager wm { get; construct; }
+        public WindowManagerGala wm { get; construct; }
 
         private Meta.Display display;
         private ModalProxy modal_proxy;
@@ -53,7 +53,7 @@ namespace Gala {
             }
         }
 
-        public MultitaskingView (WindowManager wm) {
+        public MultitaskingView (WindowManagerGala wm) {
             Object (wm: wm);
         }
 
@@ -631,6 +631,7 @@ namespace Gala {
                 wm.background_group.hide ();
                 wm.window_group.hide ();
                 wm.top_window_group.hide ();
+                wm.shell_group.hide ();
                 show ();
                 grab_key_focus ();
 
@@ -693,6 +694,7 @@ namespace Gala {
                         wm.background_group.show ();
                         wm.window_group.show ();
                         wm.top_window_group.show ();
+                        wm.shell_group.show ();
 
                         dock_clones.destroy_all_children ();
 
@@ -721,7 +723,7 @@ namespace Gala {
             foreach (unowned Meta.WindowActor actor in window_actors) {
                 const int MAX_OFFSET = 200;
 
-                if (actor.is_destroyed () || !actor.visible) {
+                if (actor.is_destroyed () || !actor.visible || actor.translation_y != 0) {
                     continue;
                 }
 

src/WindowManager.vala

@@ -37,7 +37,13 @@ namespace Gala {
          */
         public Clutter.Actor top_window_group { get; protected set; }
 
-        public Clutter.Actor notification_group { get; protected set; }
+        /**
+         * The group that contains all WindowActors that make shell elements, that is all windows reported as
+         * ShellClientsManager.is_positioned_window and notifications, as well as manually added elements.
+         * It will (eventually) never be hidden by other components and is always on top of everything. Therefore elements are
+         * responsible themselves for hiding depending on the state we are currently in (e.g. normal desktop, open multitasking view, fullscreen, etc.).
+         */
+        public Clutter.Actor shell_group { get; private set; }
 
         /**
          * {@inheritDoc}
@@ -104,8 +110,6 @@ namespace Gala {
         private bool animating_switch_workspace = false;
         private bool switch_workspace_with_gesture = false;
 
-        private signal void window_created (Meta.Window window);
-
         /**
          * Amount of pixels to move on the nudge animation.
          */
@@ -253,14 +257,6 @@ namespace Gala {
             stage.remove_child (top_window_group);
             ui_group.add_child (top_window_group);
 
-#if HAS_MUTTER44
-            var feedback_group = display.get_compositor ().get_feedback_group ();
-#else
-            var feedback_group = display.get_feedback_group ();
-#endif
-            stage.remove_child (feedback_group);
-            ui_group.add_child (feedback_group);
-
             // Initialize plugins and add default components if no plugin overrides them
             unowned var plugin_manager = PluginManager.get_default ();
             plugin_manager.initialize (this);
@@ -293,8 +289,16 @@ namespace Gala {
             }
 
             // Add the remaining components that should be on top
-            notification_group = new Clutter.Actor ();
-            ui_group.add_child (notification_group);
+            shell_group = new Clutter.Actor ();
+            ui_group.add_child (shell_group);
+
+#if HAS_MUTTER44
+            var feedback_group = display.get_compositor ().get_feedback_group ();
+#else
+            var feedback_group = display.get_feedback_group ();
+#endif
+            stage.remove_child (feedback_group);
+            ui_group.add_child (feedback_group);
 
             pointer_locator = new PointerLocator (display);
             ui_group.add_child (pointer_locator);
@@ -381,12 +385,14 @@ namespace Gala {
 
             update_input_area ();
 
-            display.window_created.connect ((window) => window_created (window));
-
             var scroll_action = new SuperScrollAction (display);
             scroll_action.triggered.connect (handle_super_scroll);
             stage.add_action_full ("wm-super-scroll-action", CAPTURE, scroll_action);
 
+            display.window_created.connect ((window) =>
+                InternalUtils.wait_for_window_actor_visible (window, check_shell_window)
+            );
+
             stage.show ();
 
             plugin_manager.load_waiting_plugins ();
@@ -1164,6 +1170,20 @@ namespace Gala {
             show_window_menu (window, menu, rect.x, rect.y);
         }
 
+        private void check_shell_window (Meta.WindowActor actor) {
+            unowned var window = actor.get_meta_window ();
+            if (ShellClientsManager.get_instance ().is_positioned_window (window)
+                || NotificationStack.is_notification (window)
+            ) {
+                actor.get_parent ().remove_child (actor);
+                shell_group.add_child (actor);
+            }
+
+            if (NotificationStack.is_notification (window)) {
+                notification_stack.show_notification (actor);
+            }
+        }
+
         /*
          * effects
          */
@@ -1479,12 +1499,8 @@ namespace Gala {
             actor.remove_all_transitions ();
             actor.show ();
 
-            // Notifications are a special case and have to be always be handled
-            // (also regardless of the animation setting)
+            // Notifications initial animation is handled by the notification stack
             if (NotificationStack.is_notification (window)) {
-                clutter_actor_reparent (actor, notification_group);
-                notification_stack.show_notification (actor);
-
                 map_completed (actor);
                 return;
             }
@@ -1888,7 +1904,6 @@ namespace Gala {
         private List<Clutter.Actor>? windows;
         private List<Clutter.Actor>? parents;
         private List<Clutter.Actor>? tmp_actors;
-        private ulong switch_workspace_window_created_id = 0;
         private Clutter.Actor? out_group;
         private Clutter.Actor? in_group;
         private Clutter.Actor? wallpaper;
@@ -2002,8 +2017,9 @@ namespace Gala {
                 if (!window.showing_on_its_workspace () ||
                     move_primary_only && !window.is_on_primary_monitor () ||
                     window == moving ||
-                    window == grabbed_window) {
-
+                    window == grabbed_window ||
+                    actor.get_parent () == shell_group
+                ) {
                     continue;
                 }
 
@@ -2116,17 +2132,6 @@ namespace Gala {
 
             prepare_workspace_switch (from, to, direction);
 
-            // while a workspace is being switched mutter doesn't map windows
-            // TODO: currently only notifications are handled here, other windows should be too
-            switch_workspace_window_created_id = window_created.connect ((window) => {
-                if (NotificationStack.is_notification (window)) {
-                    InternalUtils.wait_for_window_actor_visible (window, (actor) => {
-                        clutter_actor_reparent (actor, notification_group);
-                        notification_stack.show_notification (actor);
-                    });
-                }
-            });
-
             var animation_mode = Clutter.AnimationMode.EASE_OUT_CUBIC;
 
             var x2 = -in_group.x;
@@ -2198,11 +2203,8 @@ namespace Gala {
                 return;
             }
 
-            if (switch_workspace_window_created_id > 0) {
-                disconnect (switch_workspace_window_created_id);
-                switch_workspace_window_created_id = 0;
-            }
             end_switch_workspace ();
+
             if (!is_nudge_animation) {
                 switch_workspace_completed ();
             }
@@ -2220,9 +2222,9 @@ namespace Gala {
             }
         }
 
-        private void end_switch_workspace () {
-            if (windows == null || parents == null)
-                return;
+        private bool end_switch_workspace () {
+            if ((windows == null || parents == null) && tmp_actors == null)
+                return false;
 
             unowned var display = get_display ();
             unowned var active_workspace = display.get_workspace_manager ().get_active_workspace ();
@@ -2287,10 +2289,14 @@ namespace Gala {
 
             switch_workspace_with_gesture = false;
             animating_switch_workspace = false;
+
+            return true;
         }
 
         public override void kill_switch_workspace () {
-            end_switch_workspace ();
+            if (end_switch_workspace ()) {
+                switch_workspace_completed ();
+            }
         }
 
         public override void locate_pointer () {