This looks bad: http://people.mozilla.org/~jmuizelaar/foom.mov

[Tracking Requested - why for this release]: Looks bad

Florin can your team have a look at whether this happens in 41 as well, and try to find a regression window? Philipp, might you help find an owner for this bug?

I can reproduce this but only on a Mac Retina display. I'll keep the needinfo so we look for a regression window once the Macbook is free (currently used in ESR 38.2 sign off testing).

I can't reproduce this, but I'm on Windows. Opportunistically adding it to the QX list.

I managed to get a regression window for this today: mozilla-central Last good revision: baa9c64fea6f (2015-05-28) First bad revision: f986e55c4e0b (2015-05-29) Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=baa9c64fea6f&tochange=f986e55c4e0b mozilla-inbound Last good revision: 223975f99ca3 First bad revision: 8225a3b75df6 Pushlog: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=223975f99ca3&tochange=8225a3b75df6 Bug 1108648 stands out from the pushlog as the likely cause for this issue. Simple steps to reproduce: 1. Open Firefox and start typing "qqqqq" in the search field. -> you will notice how search suggestions display until the 5th character is entered. 2. Delete the 5th "q" character from the search field using Backspace. Actual result: the first horizontal gray bar from the top increases in height, and search suggestions are no longer displayed (I think this is the more serious issue here, as you need to restart Firefox to once again get search suggestions). Expected results: search suggestions pop up once again and horizontal gray bars keep their normal height. This can be easily reproduced with the latest Firefox 41 Aurora (BuildID=20150810004008) using a Macbook with Retina display, but it does NOT reproduce on normal Mac displays (or Windows).

[Tracking Requested - why for this release]: It can cause search suggestions (from the search field) to disappear in special case (will not work again until Firefox is restarted).

Duplicate of bug 1181868, but the fix is in progress in bug 1179234. Afaik, this can only be reproduced on OS X on retina screen.

No need to track this bug as the original bug 1181868 is tracked and bug 1179234 is fixed and verified on FF41 and 42. Thanks!