How to reproduce:
1. Create and open a new project
2. Enter Play Mode
3. Select the "Main Camera" in the Hierarchy
4. Open the Game view and open its Statistics panel by toggling the "Stats" button in the top right of the Game view
5. Note the FPS
6. Move the mouse cursor in the Inspector window and while doing that note the FPS again in the Statistics window

Expected result: The FPS is the same when moving the cursor inside the Inspector and when the cursor is stationary
Actual result: The FPS drops by 25% or more when moving the cursor in the Inspector

Reproducible with: 2019.3.39f1, 2020.3.35f1, 2021.3.3f1, 2022.1.2f1, 2022.2.0a15

Reproducible on: Ubuntu 20.04, Windows 10

Notes:
1. Performance drops can also be observed when Profiling the Editor
2. There is also a slight performance drop when moving the cursor in the Inspector without a GameObject selected but its much less noticable