Since JRE 1.6.0_18, JMenus at JMenuBar are not selectable by their Mnemonic key anymore.
How to reproduce (Testcase is attached):
OS: Windows Vista
with JRE 1.6.0_17 (or any earlier version):
Press the Alt-key, the JMenuBar is selected. If you press "e" or "s" (the mnemonik keys for the JMenus), the submenu will be visible to the user. That behavior is also native Windows behavior (Notepad for example).
with JRE 1.6.0_18:
Press the Alt-key, the JMenuBar is selected. If you press "e" or "s" (the menemonik keys for the JMenus), nothing happens.
In both cases (_17 and _18), you can open the submen by entering Alt-e or Alt-s.
The issue can be reproduced on Solaris 10 as well (use the F10 key rather than the Alt-key).