Affected versions

• Nightly 96.a1
• Beta 95.0b2
• Release 94.0

Affected platforms

• macOS 10.15
• macOS 11

Preconditions

Dark mode enabled at OS level.

Steps to reproduce

1. Open a Firefox with a clean profile.

2. Install a theme from Recommended Themes ( I used A color Within Another Color, rusty, Purple and Gold Marble)

3. Go to about:support and click on "Troubleshoot Mode..." (make sure you have two-three tabs opened).

4. Click on Restart.

Expected result

• All open tabs are visible. All suggestions in the search dropdown are visible on hover.

Actual result

• Only the focused tab is visible. Suggestions are not visible on hover.

Suggested Severity

• S2 - because it visually affects users on a very used area

Regression range

• I will look for a regression as soon as possible.

Additional notes

• Screen cast attached to observe the issue.
• I can reproduce this on Windows 10X64, with the difference that the focused tab is not visible., but all the others are. On Windows I cannot reproduce this issue on Release 94.0, only on latest Nightly 96.0a1 and Beta 95.0b2.

The Bugbug bot thinks this bug should belong to the 'Firefox::Theme' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

I reached to the following regression range for macOS:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=b8b54a4990d7e778b82909a871e92031a4bc649d&tochange=4b3932f9c4f5d9572da2f0232375474133191500

For Windows the potential regressor is Bug 1733569:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=1ff04e10cd2318b494c0f05777cd80291289d127&tochange=d39b23efefe7e7d89d8dfd0ba188ad6af2b0a9ed

:giorgia.moldovan, since this bug is a regression, could you fill (if possible) the regressed_by field?
For more information, please visit auto_nag documentation.

Unfortunately I am not sure what is the potential regressor for the macOS issue, I only suspect is Bug 1715619.

Giving the fact that there are two regression ranges on different builds, I will treat this bug for macOS and I will log a new one for Windows.

Yeah that's the regressor but the root cause is is the same as the other bug so let's track them together