Every once in a while I get a call from a user complaining, he can no longer find a certain menu in the browser -- or in Thunderbird -- and I have to painstakingly guide him on re-enabling the menu-panels.
This happens often enough to be annoying, but not often enough for him to still remember, how to do it, by the next occurrence...
No one knows, how he manages to hide the menu-panels accidentally...
Hence the question -- perhaps, the menus can be "frozen", so that their removal (hiding) cannot be achieved easily by accident? Some about:config nob, perhaps?
