Reproduction steps:
1. Open the attached project "ReproProj"
2. Move the Editor window to the secondary display with a lower resolution
3. Open the “/Assets/Scenes/RUNNERSCENES/STAR.unity” Scene
4. In Hierarchy, select “StarHandler > UI > Canvas > Background“
5. In Inspector, select “Color”
Expected result: Color window opens in the same display as the Editor window
Actual result: Color window opens in primary display
Reproducible with: 6000.0.58f1
Not reproducible with: 6000.2.6f1, 6000.3.0b4, 6000.4.0a1
Testing environment: Windows 10 Enterprise 21H2
Not reproducible on: No other environment tested