Affected versions

• 85.0a1(2020-11-24), 84.0b4;

Affected platforms

• macOS 10.15, Windows 10;

Steps to reproduce

• OS theme is set to dark;

1. Launch Firefox, set it to Firefox AlpenGlow theme;
2. Add multiple bookmark separators;

Expected result

• bookmark separators are visible;

Actual result

• bookmark separators are not visible;

Regression range

• First bad: 2020-11-21;
• Last good: 2020-11-20;
• mozregression points towards Pushlog: URL
• Potential regressor: bug 1672088;

Additional notes

• 83.0 not affected;
• S3 as suggested severity;
• attached screenshot with the issue.

Another thing worth pointing out, is that with this setup; the bars where not as visible even before the "regression"-patch.
In the image you can notice a build prior to the patch above, and the current build bellow.

(In reply to Cristian Fogel, QA [:cfogel] from comment #0)

Regression range

• First bad: 2020-11-21;
• Last good: 2020-11-20;
• mozregression points towards Pushlog: URL
• Potential regressor: bug 1672088;

That's is a macOS-only bug and your first screenshot is on Windows, so the above range seems wrong.

Is there dupe for this bug?

Unclear why this was marked wontfix for 84; a fix is likely just a 1 or 2-line CSS or theme manifest change.

I don't understand off-hand if this is different to bug 1679136. I'll investigate later today.

bug 1672088 landed immediately after bug 1667787 so I think this is a dupe.