Tested in 98.0 on Windows 7.

STR:

1. Confirm that Firefox is currently on a light theme in about:preferences.
2. Either download a content-type whose action is set to "Always ask", or flip browser.download.improvements_to_download_panel to false and then download any random file.
3. Set the active theme to a dark theme and repeat step 2 of the STR.

Expected Behavior:

See first screenshot (taken from FF97).

Actual Behavior:

See second screenshot.

STR is not reproducible when using a dark theme, but the highlight does look proton-stylized. I am not sure if this issue is reproducible on other versions of Windows.

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

I am going to guess that this was regressed by bug 1749712.

Set release status flags based on info from the regressing bug 1749712

:dao, since you are the author of the regressor, bug 1749712, could you take a look?
For more information, please visit auto_nag documentation.

Hello,

I can confirm the issue is also reproducible on the latest Nightly (100.0a1/20220320213921), Beta (99.0b6/20220320185956) and Release (98.0.1/20220313140707) on Windows 10 x64.

With a Light theme enabled and browser.download.improvements_to_download_panel set to false, I attempted to download the installer of a random Firefox browser (for example https://ftp.mozilla.org/pub/firefox/releases/98.0b9/win64/en-US/) and the results are as mentioned in the original description.

I’ve also tested Beta 97.0 and the issue does not reproduce on that version.

With a Dark theme enabled, the highlight of the buttons is indeed proton-stylized and does not appear to be affected by this bug.

For further details, please see the attached screenshots depicting the panel while using a Light theme, a Dark theme and the panel from Beta 97.0 where the issue does not occur.