[metacity] tabpopup.c: don't show shadow for outline window

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 7b13718134c32f7bdfa8aebe4fe7d63c25f32240
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Fri Oct 3 19:54:29 2014 +0300

    tabpopup.c: don't show shadow for outline window
    
    Bug: https://bugzilla.gnome.org/show_bug.cgi?id=536573

 src/ui/tabpopup.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/src/ui/tabpopup.c b/src/ui/tabpopup.c
index 99ee63a..6bd7d1f 100644
--- a/src/ui/tabpopup.c
+++ b/src/ui/tabpopup.c
@@ -225,12 +225,14 @@ meta_ui_tab_popup_new (const MetaTabEntry *entries,
   int max_label_width; /* the actual max width of the labels we create */
   AtkObject *obj;
   GdkScreen *screen;
+  GdkVisual *visual;
   int screen_width;
   
   popup = g_new (MetaTabPopup, 1);
 
   screen = gdk_display_get_screen (gdk_display_get_default (),
                                    screen_number);
+  visual = gdk_screen_get_rgba_visual (screen);
 
   if (outline)
     {
@@ -238,6 +240,9 @@ meta_ui_tab_popup_new (const MetaTabEntry *entries,
 
       popup->outline_window = gtk_window_new (GTK_WINDOW_POPUP);
 
+      if (visual)
+        gtk_widget_set_visual (popup->outline_window, visual);
+
       gtk_window_set_screen (GTK_WINDOW (popup->outline_window),
                              screen);