User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0 Build ID: 20180905123750 Steps to reproduce: 1) Open Web Developer Tools (Ctrl+Shift+i) 2) Zoom / Scale text size in Devtools by pressing Ctrl+Plus Actual results: Devtools UI flickers randomly: https://imgur.com/SVhg0PI (Nightly 64.0a1 b 20180905123750, Win 10, Intel HD)

Thank you! :) (Have seen it here: https://www.youtube.com/watch?v=6WJ70QXreWI&t=12m12s) mozregression --good 2018-09-01 --bad 2018-09-05 > 9:02.03 INFO: Last good revision: 873f58fff17d0551455eeb36614b91d197c47dbc > 9:02.03 INFO: First bad revision: 716d49302a28f9231c628a1dca5a744437403948 > 9:02.03 INFO: Pushlog: > https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=873f58fff17d0551455eeb36614b91d197c47dbc&tochange=716d49302a28f9231c628a1dca5a744437403948 > 716d49302a28 Miko Mynttinen — Bug 1413546 - Fix e10s logic in nsLayoutUtils::AreRetainedDisplayListsEnabled() and set layout.display-list.retain.chrome to true r=mattwoodrow