I've disabled "tabs on top" in Firefox 4, but it seems that double-clicking an empty area in the tab bar still behaves as if it was the title bar, so the effect is toggling window maximization.
I grew used to the Firefox 3.x behavior, which is to open a new tab when double-clicking an empty area in the tab bar; however, I could not find any way to restore that option in the Firefox options or even in
about:config. Is it at all possible, and if it is, how?
EDIT turns out it's a known bug with Firefox 4 on windows.