User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

followed the steps laid out here: https://mozillagfx.wordpress.com/2020/02/18/challenge-snitch-on-the-glitch-help-the-graphics-team-track-down-an-interesting-webrender-bug/

gfx.webrender.all => true
gfx.webrender.enabled => true

restarted firefox

Actual results:

glitches appeared in the all my tabs the loaded from the previous session.

For me it seems the window redraw is having an issue with handling the alpha of everything on the screen. for example I have windows open in the background or drawn behind the open instance of firefox and those seem to be alpha blended in conjunction with the firefox window. I also notice behavior where if it's glitchy and I move my mouse to the top window border (the system application bar) about one second later the glitch leaves almost as if there is a delayed redraw call that fixes it after a mouse-out event or something.

Expected results:

The window shouldn't have glitching artifacts.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Are you able to reproduce this in the latest Nightly? https://www.mozilla.org/en-CA/firefox/channel/desktop/

I did a fresh download of nightly, and followed the same steps to enable gfx.webrender and had the same results (as in the previously submitted image) immediately when the window opened.

(In reply to Jessie [:jbonisteel] plz needinfo from comment #3)

Are you able to reproduce this in the latest Nightly? https://www.mozilla.org/en-CA/firefox/channel/desktop/

I did a fresh download of nightly, and followed the same steps to enable gfx.webrender and had the same results (as in the previously submitted image) immediately when the window opened.

We have a suspected fix shipping in Firefox 75 (bug 1617083)

This particular glitch may be different, so if this still happens in 75 we can re-open and investigate.