Affected versions

• 77.0a1 (2020-04-09), 76.0b2, 75.0;

Affected platforms

• macOS 10.15, Windows 8.1/10, Ubuntu 18.04;

Steps to reproduce

1. Launch Firefox; *for nightly set browser.newtabpage.activity-stream.improvesearch.handoffToAwesomebar to false
2. Click and hold on the Arrow Button for Search (activity stream one not awesomebar/searchBar)

Expected result

• borders and shadows properly contained;

Actual result

• on hover the button exceeds the border;
• on click the border button is over the border for search section;

Regression range

• First bad: 2017-09-29;
• Last good: 2017-09-28;
• Pushlog: URL;
• Potential regressor: 1403215 seems a likely candidate, more or less seems like an oversight after changing from implementation with full colours;

Additional notes

• attached screenshot with the issue.

Whilst some of the search button is under Search's remit and code, the css here (especially that referenced in bug 1403215) is under the activity stream / new tab code base. Hence I think this is better handled there.

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is P3 (Backlog,) indicating it has been triaged, the bug's Severity is being updated to S3 (normal.)