Listener registration issues in menu items containing sub-menus

Steps to reproduce:

1) Run org.apache.pivot.tests.ContextMenuTest
2) Select "Help->About"
3) Select "Help->About" again

Result:

The console shows the following messages:

Nonexistent listener org.apache.pivot.wtk.DesktopApplicationContext$1@7acc7439 removed from org.apache.pivot.wtk.Window$WindowListenerList@4e2892b
Duplicate listener org.apache.pivot.wtk.DesktopApplicationContext$1@7acc7439 added to org.apache.pivot.wtk.Window$WindowListenerList@349b688e
Nonexistent listener org.apache.pivot.wtk.DesktopApplicationContext$1@7acc7439 removed from org.apache.pivot.wtk.Window$WindowListenerList@4e2892b
Duplicate listener org.apache.pivot.wtk.DesktopApplicationContext$1@7acc7439 added to org.apache.pivot.wtk.Window$WindowListenerList@349b688e

Sometimes it doesn't take two menu item selections to reproduce this. The same behavior can be seen in the MenuBarTest as well.