since upgrade to 4.0.1, FF doesn't recognize which plug-ins/extensions are running - so it says i have the default theme enabled, but i don't, and i can't enable it if i try! there are functional issues with theme that is now stuck "on" but i keep removing the theme that is stuck on and it adopts another (non-default) theme, few of which are even supposedly compatible with FF4. why??! if the only solution is to delete all the themes i've ever added - grrrr! this is 3rd time i'm reverting back to an OLD version! please stop releasing half-baked FF4!! i am not looking for perfection, but basic functionality for those of us who can't write code would be nice... finally, while i'm here: pages are also loading verrrrry slooowly. :(