Run the attached test on XToolkit. You would see a frame with a choice and a button. Right click inside the choice. A popup menu will open. Click on the 'FILE' submenu. The corresponding sub-menu will open. Now keep pressing 'LEFT ARROW'. During first press, the submenu will dis-appear. Press it again. You will get the following exception:

java.lang.NullPointerException
at sun.awt.X11.XBaseMenuWindow.doHandleJavaKeyEvent(XBaseMenuWindow.java:1077)
at sun.awt.X11.XPopupMenuPeer.handleEvent(XPopupMenuPeer.java:219)
at sun.awt.X11.XBaseMenuWindow$3.run(XBaseMenuWindow.java:895)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:590)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:270)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:198)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:171)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:166)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:158)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:119)

Here is the PIT build:
java version "1.6.0-awt.pit-int-awt-blade"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-awt.pit-int-awt-blade-dm97671_17_May_2005_14_27-b00)
Java HotSpot(TM) Server VM (build 1.6.0-ea-b36, mixed mode)

This is not reproducible on other platforms. I reproduced it SolSparc10-JDS. Looks like 6266513 is not fixed completely.
###@###.### 2005-05-19 10:22:48 GMT