Affected versions

• 82.0, 83.0a1(2020-10-08);

Affected platforms

• Windows 10, macOS 11.0;

Steps to reproduce

1. Launch Firefox;
2. Customize and add Search bar and some other items between megabar-searchbar;
3. Resize browser so that >> buttons displayed;
4. Click on the >> button;
5. Click inside the SearchBar and type any character;
6. Click on the Change Search Settings button;

Expected result

• about:preferences#search page loaded and any (overflow) menu is dismissed;

Actual result

• overflow menu remains in view;

Regression range

• will check and provide one asap;

Additional notes

• issue does not reproduce if browser is maximized;
• attached recording with the issue;
• S4 as suggested severity.

I don't think this is a regression because I can reproduce the issue with Firefox 56.0a1(20170616030207) on Windows 10x64 when the Overflow menu was introduced. Removing the flags accordingly.

The legacy search bar is not a top priority, and this is an edge case due to the overflow menu.

Probably the same cause or very similar as bug 1490614.