[gnome-shell] windowPreview: Avoid LEAVE events triggered by grab of our own StButton

[Marge Bot <marge-bot src gnome org>]

commit 95f4a1ecd6bdabf6d6ee68c42dec389799c6bdb2
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Mon Mar 7 12:14:52 2022 +0100

    windowPreview: Avoid LEAVE events triggered by grab of our own StButton
    
    Since the ClutterGrab rework, grabbing properly emits crossing events.
    
    StButtons take a ClutterGrab as soon as they are pressed, so pressing
    the close StButton of the WindowPreview takes a grab and causes a
    LEAVE+key-focus-out event getting sent to the WindowPreview. This in
    turn makes us hide our overlay (which the StButton is part of). We
    automatically ungrab ClutterGrabs when hiding actors, so the StButtons
    grab now gets released again, key-focus and hover state are updated
    again and we emit an ENTER event to the WindowPreview. The preview now
    tries show its overlay again and things explode because we re-enter the
    mapping machinery.
    
    For the LEAVE event we can break this cycle by detecting the GRAB_NOTIFY
    crossing event of our own StButton and not reacting to that.
    
    We should do the same for the key-focus-out event, but these don't pass
    context information like a GRAB_NOTIFY flag yet, so just check the
    current grab actor here.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3165
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2231>

 js/ui/windowPreview.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/windowPreview.js b/js/ui/windowPreview.js
index 373000075d..228189b18c 100644
--- a/js/ui/windowPreview.js
+++ b/js/ui/windowPreview.js
@@ -553,6 +553,10 @@ var WindowPreview = GObject.registerClass({
     }
 
     vfunc_leave_event(crossingEvent) {
+        if ((crossingEvent.flags & Clutter.EventFlags.FLAG_GRAB_NOTIFY) !== 0 &&
+            global.stage.get_grab_actor() === this._closeButton)
+            return super.vfunc_leave_event(crossingEvent);
+
         if (this._idleHideOverlayId > 0)
             GLib.source_remove(this._idleHideOverlayId);
 
@@ -582,7 +586,9 @@ var WindowPreview = GObject.registerClass({
 
     vfunc_key_focus_out() {
         super.vfunc_key_focus_out();
-        this.hideOverlay(true);
+
+        if (global.stage.get_grab_actor() !== this._closeButton)
+            this.hideOverlay(true);
     }
 
     vfunc_key_press_event(keyEvent) {