[mutter] window: Don't try to move hidden attached windows

[Florian Müllner <fmuellner src gnome org>]

commit f2d7165a524a151bc25649472511f0fb5ece005c
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Mar 15 17:10:38 2019 +0100

    window: Don't try to move hidden attached windows
    
    When a parent window is moved, attached windows (attached modal dialogs
    or popups) is moved with it. This is problematic when such a window
    hasn't been shown yet (e.g. a popup that has been configured but not
    shown), as it'll mean we try to constrain an empty window. Avoid this
    issue by not trying to auto-move empty windows.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/496

 src/core/window.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/core/window.c b/src/core/window.c
index 62b2df810..b85db6ee3 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -3781,6 +3781,9 @@ static gboolean
 maybe_move_attached_window (MetaWindow *window,
                             void       *data)
 {
+  if (window->hidden)
+    return FALSE;
+
   if (meta_window_is_attached_dialog (window) ||
       meta_window_get_placement_rule (window))
     meta_window_reposition (window);