Steps to reproduce:
1. Create a project
2. Create a Material (Create > Material)
3. Open Base Map Color window of the newly created Material
4. Select a random color, add it to the Swatches list by pressing on the rectangle with the selected color
5. Create few more Swatches and select one of them

Actual results: Black line briefly appears on the color Swatch on the left from the selected one while it’s being clicked on
Expected results: Color Swatch gets selected

Reproducible with versions: 2021.3.50f1, 2022.3.60f1, 6000.0.43f1, 6000.1.0b11, 6000.2.0a7

Tested on (OS): macOS Sequoia 15.3 (Intel)