I'm using Lubuntu with firefox in place of chromium and I experience the following problem: when I press F11 the application goes to fullscreen mode but when I subsequently press F11 the application will only partially exit fullscreen, since the menu bar is totally hidden and the tabs/toolbar appear only when I move the mouse close to the titlebar. Other applications fullscreen (e.g. geany) do not have this problem, is this a bug? is there a workaround?
I just tested with Ubuntu and I have the same issue. I tested with windows, and no problem, so I would think it a bug. there is 2 ways that you can use as a workaround:
1) Type about:config in the address bar and look for:
what that will do is keep the firefox button and tabs visible
Hope that this helps