1618683 - After switching tabs, elements from previous tab drawn over new one

Status: RESOLVED FIXED

(Core :: Graphics, defect, P2)

Description

[Molly Howell (she/her) (mostly inactive)]

Attachment: screenshot.png

On Nightly, I currently have one DuckDuckGo search tab which, when I switch to it, some elements from the tab I switched from remain drawn over the top of the DuckDuckGo tab. New DDG tabs that I create don't do this, and no other tabs that I have open seem to either, so I assume it's something with that tab. Not every tab that I switch from gets something drawn either; MSDN documentation pages seem to get parts of one or both of their sidebars stuck like this, and parts of the Gmail inbox and right sidebar do as well.

I'll attach a screenshot; note the search bar and part of the tree view from the left sidebar of the MSDN page overlaying the search results, and part of its right sidebar where the DDG page itself is empty. That split between the left and right sides always seems to be present, and it always switches over around that same vertical position.

I'll leave this browser running so I can collect any relevant information from it. I do seem to have WebRender enabled (according to about:support), and this machine is a laptop with Intel UHD 620 graphics.

Comment 1

[Molly Howell (she/her) (mostly inactive)]

It turns out any DuckDuckGo results tab will act this way, not just that one, but you have to scroll it down by some amount first (roughly enough to get the first two results off the screen).

Also, a coworker (:bytesized) with the same model laptop (a Dell XPS 13 9370) has been able to reproduce this, so maybe it isn't quite as intermittent and fragile as I was afraid it would be.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Can either of you see if you can reproduce the problem on Beta?

Comment 3

[Molly Howell (she/her) (mostly inactive)]

Working on it (and leaving needinfo until I can succeed).

Today I can't seem to reproduce in the same Nightly instance/profile either, which is pretty annoying. Although over the weekend I did see this same thing (with the same combination of pages) on a different machine which has an Nvidia 1080 in it, so that killed my guess that this might be an Intel bug.

Comment 4

[Molly Howell (she/her) (mostly inactive)]

It turns out I can only reproduce this on the nightly that I found it in (which was 20200227094956), and not on either beta or the current nightly. So there might not be anything to actually do here.

I did also confirm while checking this that it won't reproduce without WebRender enabled.