Mozilla/5.0 (Windows NT 5.1; rv:10.0a1) Gecko/20111017 Firefox/10.0a1 Mozilla/5.0 (X11; Linux i686; rv:10.0a1) Gecko/20111017 Firefox/10.0a1 Mozilla/5.0 (Windows NT 6.1; rv:10.0a1) Gecko/20111017 Firefox/10.0a1 Reproducible on Windows 7, Windows XP and Ubuntu 11.04. STR: 1. Launch Firefox Nightly with a clean profile. 2. Open https://docs.google.com/present/edit?id=0AWty6gb0hLqVZHE0cDZ3M18waGIya2t2aHA&hl=ro 3. Select the second slide. Actual result: the purple image overlaps the text. Expected result: the slide should be displayed as in the preview image in the left. The issue is not reproducible on the latest Beta, Aurora and Release. Oddly, mozregression traced the problem right back to Firefox 7 Nightly: Last good nightly: 2011-06-12 First bad nightly: 2011-06-13 Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?startdate=2011-06-12&enddate=2 011-06-13

> The issue is not reproducible on the latest Beta, Aurora and Release. Is it something that maybe got backed out of beta and aurora? If you look at Aurora and Beta nightlies, do you see the bug happen and then disappear at some point? Alternately, what happens if you use the beta or aurora UA string on m-c?

Yes, it seems that this was backed out of Aurora and Beta. Downloaded Aurora builds to see where does this came from. The last bad Firefox 9 was the nightly in 27.9.2011. Afterwards, the first Aurora did no longer have the problem (http://hg.mozilla.org/releases/mozilla-aurora/rev/91108b393572). So probably bug 611099 caused the regression. The backout concerned bug 668163.

Yeah, ok. That makes sense. Thanks for hunting that down! Let's keep track of this and retest once bug 668163 is fixed.