User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0

Steps to reproduce:

1. Open outlook.com
2. Click on the cog wheel
3. Click on "View all outlook Settings" -> "Email" -> "Layout" and scroll down

Actual results:

The page content disappears randomly, sometimes is white and if you scroll seems to fix, but other parts then become white. As if it doesn't paint some areas on scroll. See screenshots for examples.

Expected results:

Should paint everything and instantly on scroll, as if when WebRender is disabled.

I was unable to reproduce on Linux/Haswell or on Windows/AMD. Would you be willing to give mozregression a go to see if we can isolate where the change came from?

https://mozilla.github.io/mozregression/documentation/usage.html

e.g. mozregression --good 2018-06-01 --pref gfx.webrender.all:true

The --pref gfx.webrender.all bit will ensure WebRender is forced on for regression window purposes.

Wow, what a nice tool! <3

I also cannot reproduce it on latest builds, however i have searched for the fix, and this is the result:

18:40.92 INFO: Downloading build from: https://queue.taskcluster.net/v1/task/We25h2l5TBqNp4RZlYrzsw/runs/0/artifacts/public%2Fbuild%2Ftarget.tar.bz2
===== Downloaded 100% =====
18:43.55 INFO: Running autoland build built on 2019-09-24 11:28:31.956000, revision 4c4c2559
18:52.84 INFO: Launching /tmp/tmpKr0qXO/firefox/firefox
18:52.84 INFO: Application command: /tmp/tmpKr0qXO/firefox/firefox --allow-downgrade https://outlook.com/ --allow-downgrade -profile /tmp/tmpgOTq3e
18:52.84 INFO: application_buildid: 20190924101054
18:52.84 INFO: application_changeset: 4c4c25595fe8e9b234e9731128abbd4e324749d8
18:52.84 INFO: application_name: Firefox
18:52.84 INFO: application_repository: https://hg.mozilla.org/integration/autoland
18:52.84 INFO: application_version: 71.0a1
Was this inbound build good, bad, or broken? (type 'good', 'bad', 'skip', 'retry', 'back' or 'exit' and press Enter): bad
20:11.08 INFO: Narrowed inbound regression window from [ddb1fdf0, 96ce8d26] (3 builds) to [4c4c2559, 96ce8d26] (2 builds) (~1 steps left)
20:11.08 INFO: No more inbound revisions, bisection finished.
20:11.08 INFO: First good revision: 96ce8d267d27ed5a0b0b9cd7e105dcf90010d78f
20:11.08 INFO: Last bad revision: 4c4c25595fe8e9b234e9731128abbd4e324749d8
20:11.08 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=4c4c25595fe8e9b234e9731128abbd4e324749d8&tochange=96ce8d267d27ed5a0b0b9cd7e105dcf90010d78f

Cool, thanks!