Comment 24 for bug 161961

(From update of attachment 396575)
I think you want to write the ifdef blocks such that they only change behaviour on Linux.

This patch will cause the test test_menubar.xul to fail. But updating the test should be simple. There's tests there which checks that alt/F10 highlights but doesn't open the menu. Instead, they will need to check if the menu is open on Linux.

Also, do you want this both for when F10 is pressed and when Alt pressed or just the former?