Index: trunk/src/org/openstreetmap/josm/gui/util/AdvancedKeyPressDetector.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/util/AdvancedKeyPressDetector.java	(revision 7638)
+++ trunk/src/org/openstreetmap/josm/gui/util/AdvancedKeyPressDetector.java	(revision 7639)
@@ -195,5 +195,5 @@
     private boolean isFocusInMainWindow() {
         Component focused = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
-        return SwingUtilities.getWindowAncestor(focused) instanceof JFrame;
+        return focused != null && SwingUtilities.getWindowAncestor(focused) instanceof JFrame;
     }
 }