[Affected versions]: - latest Nightly 56.0a1 (2017-06-15) [Affected platforms]: - Windows 10 x64 - Mac OS X 10.11.6 [Steps to reproduce]: 1. Start Firefox. 2. Go to: https://www.youtube.com/ 3. Open "Find in page" option: Ctrl/Cmd + F 4. Start scrolling with your mouse wheel. [Expected result]: - No UI issues while scrolling [Actual result]: - Black blinking lines can be seen below the location bar and above Find bar, as soon as scrolling starts [Regression range]: Last good revision: 958d2a5d10091401fd5e900e8e063d21940c137e First bad revision: 7f894f791cdf170d788507d0eff30024ce699523 Pushlog: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=958d2a5d10091401fd5e900e8e063d21940c137e&tochange=7f894f791cdf170d788507d0eff30024ce699523 Looks like the following bug has the changes which introduced the regression: https://bugzilla.mozilla.org/show_bug.cgi?id=1370430 [Additional notes]: - reproducible only with e10s enable - Ubuntu is not affected by this issue

> Looks like the following bug has the changes which introduced the regression: > https://bugzilla.mozilla.org/show_bug.cgi?id=1370430 Kartikaya, can you please take a look at this? Thanks!

(In reply to Ciprian Georgiu, QA [:ciprian_georgiu] from comment #0) > Looks like the following bug has the changes which introduced the regression: > https://bugzilla.mozilla.org/show_bug.cgi?id=1370430 How did you come to this conclusion? The regression range you posted doesn't include this bug, and has a number of other bugs.

Oh, it looks like the output is from mozregression. But the output (and mozregression) is wrong. Is it possible for you to narrow down the range any more?

(In reply to Kartikaya Gupta (email:kats@mozilla.com) from comment #3) > Oh, it looks like the output is from mozregression. But the output (and > mozregression) is wrong. Is it possible for you to narrow down the range any > more? I ran again the mozregression and it points me the same bug https://bugzilla.mozilla.org/show_bug.cgi?id=1370430 and same regression range. It seems that, I can't go any further with the range because I am getting this message in console "Oh noes, no (more) inbound revisions :(".

Ok. I'll finish the bisection with local builds, if I can.

This is a regression from bug 1361970, based on a local build of cset 68932b1a5b71 with the WR backout (cset 7f894f791cdf) cherry-picked on top of it. If I do a build at cset 1561522b1179 (which is the parent of 68932b1a5b71) with the WR backout, the issue doesn't manifest. Note that the "black flickering line" is one 1 pixel high, at least for me. It's not very visible unless you're looking for it.

Dupe of bug #1373335