[Update: this bug was first found on HDRP / Compositor, but it is a general issue with the mouse position when multiple editor windows are involved. See the comment section for more details].

Focus moves in Hierarchy on changing Key Color of Chroma Keying under Input Filters section in Graphics Compositor window.

Steps to repro:
1. Create a new project.
2. Windows > Render Pipeline > Graphics Compositor.
3. Enable Compositor > INput Filters > Chroma Keying.
4. Key Color > Click on Color Palette >
5. Click & Drag on the Color Section.

Actual Result:
Focus moves in Hierarchy on changing Key Color of Chroma Keying.

Expected Result:
Focus should not move in Hierarchy on changing Key Color of Chroma Keying

Reproducible in:
2020.2.0b2 with Package Version 10.0.0-preview.27, 9.0.0-preview.54

Working Fine in:
2020.2.0b1 with Package Versio 10.0.0-preview.27,
2020.1.5f1 with Package Version 9.0.0-preview.54.

Environment:
Occurring only on Windows 10.