Missing sides on boxes on codesandbox.io

[bogas04]

I'm using WebRender on Nightly (OSX) and found a rendering issue while browsing on https://codesandbox.io. The sides of the boxes aren't getting filled with the background-color.

Refer to this tweet: https://twitter.com/bogas04/status/931450562410770432?s=17

[kvark]

Thanks for filing the issue! We seem to be improperly transforming 3d contexts here.

[Darkspirit]

mozregression --find-fix --bad 2017-11-17 --good 2018-01-15 --pref layers.acceleration.force-enabled:true gfx.webrender.enabled:true gfx.webrendest.enabled:true gfx.webrender.blob-images:true image.mem.shared:true layout.display-list.retain:false startup.homepage_welcome_url:"https://codesandbox.io/"

8:01.60 INFO: First good revision: 8ccb0e9d9bbeeed7d7e4474849debd7d21b65971
8:01.60 INFO: Last bad revision: c174ef283f5561aa3cf24b1d014b5f62dcd5ccd4
8:01.60 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c174ef283f5561aa3cf24b1d014b5f62dcd5ccd4&tochange=8ccb0e9d9bbeeed7d7e4474849debd7d21b65971

da9b75fc0866 Kartikaya Gupta — Bug 1426116 - Update webrender to commit a422f90. r=jrmuizel

Fix range: 1142dfc...a422f90

Possibly fixed by #2250.

Thank you! :)