How to reproduce:
1. Open the attached project "handlesRepro"
2. In the macOS Menu bar, select "Gakuso > TEST"
3. In the TEST window, click and drag the Handles

Expected result: The Handles move and rotate the cube
Actual result: The Handles cannot be interacted with

Reproducible with: 2020.3.22f1, 2021.1.28f1, 2021.2.0a16
Not reproducible with: 2021.2.0a17, 2021.2.2f1, 2022.1.0a15
Could not test with: 2019.4.32f1 (Console error: (Assets/TEST1.cs(30,54): error CS1501: No overload for method 'Instantiate' takes 0 arguments))

Note: The Handles in the affected versions can be interacted with by clicking and dragging the cursor below the Handles, as the controls are offset to the bottom.