ModalProxy: Explicitly allow window groups

lib/WindowManager.vala

@@ -38,6 +38,12 @@ namespace Gala {
         MEDIA_KEYS
     }
 
+    public enum WindowGroup {
+        DESKTOP_SHELL,
+        MODAL,
+        OVERLAY,
+    }
+
     /**
      * A minimal class mostly used to identify your call to {@link WindowManager.push_modal} and used
      * to end your modal mode again with {@link WindowManager.pop_modal}
@@ -46,6 +52,7 @@ namespace Gala {
         public Clutter.Grab? grab { get; set; }
 
         private ModalActions allowed_actions;
+        private WindowGroup[] allowed_window_groups;
 
         public ModalProxy () {
         }
@@ -57,6 +64,14 @@ namespace Gala {
         public bool filter_action (ModalActions action) {
             return !(action in allowed_actions);
         }
+
+        public void allow_window_groups (WindowGroup[] window_groups) requires (grab == null) {
+            allowed_window_groups = window_groups;
+        }
+
+        public bool is_window_group_allowed (WindowGroup window_group) {
+            return window_group in allowed_window_groups;
+        }
     }
 
     public interface WindowManager : Meta.Plugin {

src/Widgets/ModalGroup.vala

@@ -14,6 +14,8 @@
  * instead to {@link window_group}.
  */
 public class Gala.ModalGroup : Clutter.Actor {
+    private const WindowGroup[] ALLOWED_WINDOW_GROUPS = { MODAL, OVERLAY };
+
     public WindowManager wm { private get; construct; }
     public ShellClientsManager shell_clients { private get; construct; }
 
@@ -71,6 +73,7 @@ public class Gala.ModalGroup : Clutter.Actor {
             visible = true;
             modal_proxy = wm.push_modal (this, false);
             modal_proxy.allow_actions (ZOOM | LOCATE_POINTER | SCREENSHOT | SCREENSHOT_AREA | SCREENSHOT_WINDOW);
+            modal_proxy.allow_window_groups (ALLOWED_WINDOW_GROUPS);
         }
 
         if (dimmed.size == 1) {

src/Widgets/MultitaskingView/MultitaskingView.vala

@@ -22,6 +22,7 @@
  */
 public class Gala.MultitaskingView : Root, RootTarget, ActivatableComponent {
     public const int ANIMATION_DURATION = 250;
+    private const WindowGroup[] ALLOWED_WINDOW_GROUPS = { DESKTOP_SHELL, OVERLAY };
 
     private GestureController workspaces_gesture_controller;
     private GestureController multitasking_gesture_controller;
@@ -234,6 +235,7 @@ public class Gala.MultitaskingView : Root, RootTarget, ActivatableComponent {
 
             modal_proxy = wm.push_modal (get_stage (), false);
             modal_proxy.allow_actions (MULTITASKING_VIEW | SWITCH_WORKSPACE | ZOOM | LOCATE_POINTER | MEDIA_KEYS | SCREENSHOT | SCREENSHOT_AREA);
+            modal_proxy.allow_window_groups (ALLOWED_WINDOW_GROUPS);
         } else if (action == MULTITASKING_VIEW) {
             DragDropAction.cancel_all_by_id ("multitaskingview-window");
         }

src/WindowManager.vala

@@ -18,12 +18,6 @@
 
 namespace Gala {
     public class WindowManagerGala : Meta.Plugin, WindowManager {
-        public enum WindowGroup {
-            DESKTOP_SHELL,
-            MODAL,
-            OVERLAY,
-        }
-
         private const string OPEN_MULTITASKING_VIEW = "dbus-send --session --dest=org.pantheon.gala --print-reply /org/pantheon/gala org.pantheon.gala.PerformAction int32:1";
         private const string OPEN_APPLICATIONS_MENU = "io.elementary.wingpanel --toggle-indicator=app-launcher";
 
@@ -721,12 +715,18 @@ namespace Gala {
         private void on_focus_window_changed () {
             unowned var display = get_display ();
 
-            if (!is_modal () || modal_stack.peek_head ().grab != null || display.focus_window == null ||
-                ShellClientsManager.get_instance ().is_shell_window (display.focus_window)
-            ) {
+            if (!is_modal () || modal_stack.peek_head ().grab != null || display.focus_window == null) {
                 return;
             }
 
+            if (overridden_window_group.has_key (display.focus_window)) {
+                var overridden_group = overridden_window_group[display.focus_window];
+
+                if (modal_stack.peek_head ().is_window_group_allowed (overridden_group)) {
+                    return;
+                }
+            }
+
             display.unset_input_focus (display.get_current_time ());
         }