[mutter] Don't constantly restack hidden windows

[Owen Taylor <otaylor src gnome org>]

commit 1a276a2ee5cbe05b96bcf0cea1f64c212a77679b
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Wed Jan 26 16:35:18 2011 -0500

    Don't constantly restack hidden windows
    
    A logic bug was resulting in the bottom hidden window (hidden means means
    minimized or on a different workspace) continually being stacked above
    the other hidden windows.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=640679

 src/compositor/compositor.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index 058114b..c9dc83a 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -974,7 +974,10 @@ meta_compositor_sync_stack (MetaCompositor  *compositor,
 
           if (old_window->hidden &&
               !meta_window_actor_effect_in_progress (old_actor))
-            old_stack = g_list_delete_link (old_stack, old_stack);
+            {
+              old_stack = g_list_delete_link (old_stack, old_stack);
+              old_actor = NULL;
+            }
           else
             break;
         }