Comment 27 for bug 1097763

I can reproduce the problem twitter attachment 701462 in Firefox18.0 and Firefox 19beta, but not in Aurora20.0a2 and Nightly21.0a1.

Regression window(m-c)
Good:
http://hg.mozilla.org/mozilla-central/rev/6fa6e55a93b2
Mozilla/5.0 (X11; Linux i686; rv:20.0) Gecko/20121204 Firefox/20.0a1 ID:20121204030754
Bad:
http://hg.mozilla.org/mozilla-central/rev/1942b4d64dc8
Mozilla/5.0 (X11; Linux i686; rv:20.0) Gecko/20121205 Firefox/20.0a1 ID:20121205030759
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=6fa6e55a93b2&tochange=1942b4d64dc8

Regression window(aurora channel)
Good:
http://hg.mozilla.org/releases/mozilla-aurora/rev/fe20163490ec
Mozilla/5.0 (X11; Linux i686; rv:19.0) Gecko/20121207 Firefox/19.0a2 ID:20121207042017
Bad:
http://hg.mozilla.org/releases/mozilla-aurora/rev/e8c2cb8c583f
Mozilla/5.0 (X11; Linux i686; rv:19.0) Gecko/20121208 Firefox/19.0a2 ID:20121208042017
Pshlog:
http://hg.mozilla.org/releases/mozilla-aurora/pushloghtml?fromchange=fe20163490ec&tochange=e8c2cb8c583f

Regression window(beta channel)
Good:
http://hg.mozilla.org/releases/mozilla-beta/rev/b5fab1c304d2
Mozilla/5.0 (X11; Linux i686; rv:18.0) Gecko/20121207 Firefox/18.0 ID:20121207003552
Bad:
http://hg.mozilla.org/releases/mozilla-beta/rev/4e486ec47f47
Mozilla/5.0 (X11; Linux i686; rv:18.0) Gecko/20121208 Firefox/18.0 ID:20121208005051
Pshlog:
http://hg.mozilla.org/releases/mozilla-beta/pushloghtml?fromchange=b5fab1c304d2&tochange=4e486ec47f47

in local build
Last Good: 735426e182ac
First Bad: b64693f63118
Triggered by:
b64693f63118 Matt Woodrow — Bug 810302 - When flattening layers together to avoid component alpha, attempt to pick the 'best' active scrolled root to minimize invalidation during scrolling. r=roc, a=lsblakk

And I also confirmed fixed range in comment#6.