Affected versions

• Fx89.0b5
• Fx90.0a1

Affected platforms

• Ubuntu 18.04

Steps to reproduce

1. Enable High Contrast at OS level.
2. Launch Firefox.
3. Navigate to about:support and inspect the page.

Expected result

• All the elements of the page are visible.

Actual result

• Left column of the about:support table is not visible.

Regression range

• This is not a regression. It is happening with the proton implementation.

Additional notes

• The issue does not ocur on Windows High Contrast.
• The issue does not occur in Fx88.0b9.

Just to clarify from your comment above "This is not a regression. It is happening with the proton implementation." you meant to say that it's NOT a proton regression, right?

Wanted to comment and say that this happens in macOS with high contrast enabled in Accessibility settings; I have a screenshot here: https://bugzilla.mozilla.org/show_bug.cgi?id=1700983#c4

I was unable to replicate this bug on Ubuntu and on the latest version of nightly. Can you still replicate this bug?

Here is the regression:
14:29.18 INFO: First good revision: 0f1b7efa93371038b59694094cff99430c83d93c
14:29.18 INFO: Last bad revision: 4d09a5a6a6ec3b0b970152c87f8908b105e34c3d
14:29.18 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=4d09a5a6a6ec3b0b970152c87f8908b105e34c3d&tochange=0f1b7efa93371038b59694094cff99430c83d93c

Unfortunately I no longer posses the machine from which I reported the issue and I only have an Ubuntu 20.04. On my current machine (Ubuntu 20.04), on the lastest nightly - Fx 95.0a1, the issue no longer occurs.

If this no longer reproduces on 20.04, I don't think there's anything we can really do with it. Thanks, everyone.