Affected versions

• 92.0a1 (2021-07-22)

Affected platforms

• Win10 - confirmed so far;

Steps to reproduce

1. Launch Firefox, right click on toolbar;
2. Click on the Manage bookmarks option to open up the Library;
3. Click inside the search bookmarks box;

Expected result

• elements in the window are consistent one with another;

Actual result

• default state for input-boxes should be the same but before clicking in the Search Bookmarks field -> it lacks the border(as seen on the Name, URL, Tags, Keyword fields);

Additional notes

• attached screenshot with the issue;
• visible on dark theme setup, did not check for light theme scheme;
• poking the QA team for further investigation.

I've managed to reproduce the issue on Windows 10x64, and then investigated for the change that made this behavior possible:
2021-07-26T16:11:10.572000: DEBUG : Found commit message:
Bug 1705967 - Overhaul and protonize the library window for Windows r=mak,desktop-theme-reviewers,harry

Differential Revision: https://phabricator.services.mozilla.com/D112490

2021-07-26T16:11:10.572000: DEBUG : Did not find a branch, checking all integration branches
2021-07-26T16:11:10.575000: INFO : The bisection is done.
2021-07-26T16:11:10.577000: INFO : Stopped

There isn't an official spec here, but the search field looks like the urlbar/searchbar and that is ok.
The input fields look like the edit bookmarks panel, and that's also ok.

I don't see a bug here, we don't have any mandatory styling saying that the search bar must look like other input fields.