Do the following to reproduce the bug:

Run the attached sample code. You will see a button and a choice. Click on the button. This will make the choice unfocusable. Now click on the choice. The drop-down will appear. Move the mouse over one of the items and make sure it gets highlighted. Move the mouse out of the drop-down (the item should still remain highlighted). Now press 'SPACE BAR'. You will see an IllegalArgumentException on the console.

This is reproducible only on Win32 and I reproduced it using Mustang-b72. It is also reproducible on b75 PIT build. This is not reproducible on XToolkit.

Here is the exception:
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: illeg
al Choice item position: -1
at java.awt.Choice.select(Choice.java:413)
at sun.awt.windows.WChoicePeer$1.run(WChoicePeer.java:85)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)