Support keyboard menu usage

[KonradHoeffner]

When I press the ALT key, in most applications the menu shows up. However this doesn't work in Protégé, would it be possible to support that? When I click the menu with the mouse, I can navigate it with the keyboard but there are no shortcuts, for example I would assume w would open the Window menu. Using Gnome on Arch Linux here, don't know if that is relevant.