Comment 21 for bug 251617

same here since Intrepid, F11 works.

Seems it happened the first time when I maximized firefox window, then closed it and opened it the next session.
After that, unmaximize didn't work properly, and maximizing again would give the same windowless result.

After unmaximize + resize (to smaller window), then close, then open again, things seem to be ok.