It was quite a while ago when I upgraded my pre-ancient Ubuntu box. The upgrade itself is worth a song or two. I did hoary to breezy to dapper to edgy to feisty, step-by-step as it is recommended. To be honest I expected the upgrade stunt to fail as my box was not even close to vanilla Ubuntu. However, I thought I give it a try.

And, lo and behold, after a few twists (which I probably would have avoided if my box hadn't been "tuned") it came out fine except that Firefox did not display flash animations. They were there (I could hear the sound) but invisible. Finally yesterday I decided to get my flash back. :-)

It did not take very long to narrow it down to adblock's "Obj-Tabs" option. Turning it off fixed flash animations. I filed a bug and informed adblock developers as I could not find any indication of the bug on adblock website. Just a minute ago I found out that mozillaZine forums know about the problem and the "disable obj-tabs" solution.