V 0.92 is out. It fixes a bug related to flash : when the whole content of a page is a flash animation, it captures keyboard and mouse events to an extent it was impossible to switch back to normal screen mode or even to another tab. Download it through this link or ask Firefox to update it through the extensions panel. /* enjoy */

So the adress bar, tabs and status bar are forced visible in such a case.

UPDATE: because of a bug impacting switch between tabs, there is now a 0.93 fixing it.