I just experienced a very odd behavior with Firefox on my system. Somehow, my titlebar had disappeared. I chose to ignore this as an odd glitch, figured it would go away when Firefox was restarted, and went about my work.
Eventually, it started to drive me nuts. Not only was the titlebar missing, but I could not resize Firefox, could not move Firefox, and it kept stealing focus from other applications and obscuring new windows.
Even at this point, I did not want to restart Firefox yet, so I kept just ignoring it. Then, Firefox froze entirely. It seems like I could still interact with Firefox via the keyboard (since the titles in the Window List panel kept changing), but the rendered image of Firefox never changed.
Restarting Firefox didn’t work. Restarting the system didn’t work. Changing from Emerald to Metacity (run “metacity –replace”) didn’t work. Uninstalling some new packages didn’t work. I was at a loss.
I settled back into just dealing with the problem, when I happened to accidentally switch Firefox to fullscreen (F11). Amazingly, when I switched back to normal, the problem went away.
So, the quick way to fix the problem of a missing titlebar in Firefox with Ubuntu (this problem may be present in other distros as well) is to switch to fullscreen and then back. Basically, you can press F11 twice to fix it.
Did I help you?