STR: 1. install this addon : https://addons.mozilla.org/en-US/firefox/addon/custom-image-backgrounds/ 2. open any image in Firefox like : https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-ash3/560634_321538887959410_482280341_n.jpg 3. Hover over the top left triangle 4. In Firefox 17, it animates to first come out and then rotate to a side pane. 5. In Nightly, it directly appears as a side panel. 6. While in both Firefox versions, the returning animation is perfectly fine. (rotate and slide in)

Did you confirm that bug 539356 caused this? or just a hunch?

Is there a way to actually confirm ? If yes, I will do that. but I tried to rule out other possibilities as much as I can.

The best thing you could do is bisect this problem down to a single days changesets using nightly builds. http://mozilla.github.com/mozregression/ can automate much of the work for you. Or if that is too much work you can try aurora and beta to see if they are broken too, that will narrow it down a bit further.

okay, so this happens only in Nightly builds. Aurora and Beta are fine. let me do some binary search and bring down the last good date.

(In reply to Timothy Nikkel (:tn) from comment #3) > The best thing you could do is bisect this problem down to a single days > changesets using nightly builds. http://mozilla.github.com/mozregression/ > can automate much of the work for you. > > Or if that is too much work you can try aurora and beta to see if they are > broken too, that will narrow it down a bit further. okay, so I think I got the culprit, its bug 731974, thanks for helping out, and sorry for spam.

Do the try builds here http://ftp-scl3.mozilla.com/pub/mozilla.org/firefox/try-builds/vladimir@pobox.com-fadac9dbe2a8/try-win32/ fix the problem for you? Maybe this is the same issue as bug 823091.

(In reply to Timothy Nikkel (:tn) from comment #6) > Do the try builds here > http://ftp-scl3.mozilla.com/pub/mozilla.org/firefox/try-builds/ > vladimir@pobox.com-fadac9dbe2a8/try-win32/ fix the problem for you? Maybe > this is the same issue as bug 823091. yes, I just downloaded, the problem is fixed in the try builds.

Fixed by checking of 823091