System: Windows 10, Betterbird 115.4
How it looks like:

How it is supposed to look like:

How to reproduce:
- Start Betterbird.
- See that the QuickFilter toolbar button does NOT shine. (good)
- Click the QuickFilter toolbar button.
- Click somewhere else in the Betterbird UI.
- See that the QuickFilter toolbar button does continue to shine. (bad)
- Restart Betterbird
- See that the QuickFilter toolbar button does not shine. (good).