[glade] GtkWindow: don't set the same titlebar multiple times

[Juan Pablo Ugarte <jpu src gnome org>]

commit 8953d805f4293ace36a07314d49e3aa6156bf045
Author: Ben Iofel <iofelben gmail com>
Date:   Wed Feb 17 17:06:57 2016 -0500

    GtkWindow: don't set the same titlebar multiple times

 plugins/gtk+/glade-gtk-window.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/plugins/gtk+/glade-gtk-window.c b/plugins/gtk+/glade-gtk-window.c
index fad636e..9d57c5a 100644
--- a/plugins/gtk+/glade-gtk-window.c
+++ b/plugins/gtk+/glade-gtk-window.c
@@ -246,9 +246,11 @@ glade_gtk_window_set_property (GladeWidgetAdaptor * adaptor,
 
           titlebar = gtk_window_get_titlebar (GTK_WINDOW (object));
           if (!titlebar)
-            titlebar = glade_placeholder_new ();
+            {
+              titlebar = glade_placeholder_new ();
+              gtk_window_set_titlebar (GTK_WINDOW (object), titlebar);
+            }
           g_object_set_data (G_OBJECT (titlebar), "special-child-type", "titlebar");
-          gtk_window_set_titlebar (GTK_WINDOW (object), titlebar);
 
           glade_widget_property_set_sensitive (gwidget, "title", FALSE, CSD_DISABLED_MESSAGE);
           glade_widget_property_set_sensitive (gwidget, "decorated", FALSE, CSD_DISABLED_MESSAGE);