Index: trunk/src/org/openstreetmap/josm/gui/NotificationManager.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/NotificationManager.java	(revision 10632)
+++ trunk/src/org/openstreetmap/josm/gui/NotificationManager.java	(revision 10633)
@@ -154,5 +154,8 @@
             if (currentNotificationPanel != null) {
                 currentNotificationPanel.setVisible(false);
-                ((JFrame) Main.parent).getLayeredPane().remove(currentNotificationPanel);
+                JFrame parent = (JFrame) Main.parent;
+                if (parent != null) {
+                    parent.getLayeredPane().remove(currentNotificationPanel);
+                }
                 currentNotificationPanel = null;
             }