The following navigation, activation and selection keyboard bindings on JMenuBar for proper operation and key binding sequences.

Keybindings updated 1/24

JMenuBar
Navigate in - F10 (Focus is given to first menubar item)
Navigate out - Tab, Shift+Tab (Win32 doesn't provide this)
Esc (returns focus to last component that had it)
Navigate between menubar items - Arrow keys
Post menu - D(U) Arrow key, Spacebar, Enter
Unpost menu - Esc = (unposts sub-menus one at a time, pressing
in main menu unposts the menu and
returns focus to last object that
had it)
Enter and Spacebar = causes default or selected action