[gtk+] Check for NULL pointer

[Kristian Rietveld <kristian src gnome org>]

commit c659542333d8b958a13f11867f612d08fe315ff0
Author: Kristian Rietveld <kris gtk org>
Date:   Fri Dec 24 14:45:19 2010 +0100

    Check for NULL pointer

 gtk/gtkcombobox.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index 2de10eb..753212f 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -2294,7 +2294,7 @@ gtk_combo_box_popup_for_device (GtkComboBox *combo_box,
   if (!gtk_widget_get_realized (GTK_WIDGET (combo_box)))
     return;
 
-  if (gtk_widget_get_mapped (priv->popup_window))
+  if (priv->popup_window && gtk_widget_get_mapped (priv->popup_window))
     return;
 
   if (priv->grab_pointer && priv->grab_keyboard)