How to reproduce:
1. Create a new Unity project
2. Enter the Play Mode
3. Exit the Play Mode by pressing the Play button, and move the mouse button away from the controls
4. Observe the Play button

Expected results: The Play button is not highlighted
Actual results: The Play button remains highlighted unless hovered on the controls toolbar

Reproducible with: 6000.1.0b2
Not reproducible with: 2022.3.56f1, 6000.0.34f1, 6000.1.0b1

Reproducible on: macOS Sequoia 15.1 (M1)
Not reproducible on: No other environment tested

Note: If the mouse remains close to the controls, the Play button doesn't remain highlighted