When editing a prefab in isolation, if you rename the prefab and then immediately drag + drop a material onto it in scene view, the editor will lock up. The renaming confirmation popup will be shown but you cannot interact with it and the cursor will get stuck in the wait state.

I cannot reproduce this on MacOS 10.15.6, is possibly Windows only.

2. Open the attached project
3. Open TestPrefab in isolation mode (Make sure automatic save is on)
4. In Project View, rename the prefab
5. Drag + drop the material "MaterialToApply" onto the prefab in scene view

Expected Result:
The rename prefab popup appears and the editor continues to function as normal.

Actual Result:
The rename prefab popup appears but the editor locks up.

Tested on Windows 10, MacOS 10.15.6

Occurs on 2020.1.8f1, 2020.2.0b6, 2020.2.a12, 2021.1.0a1

Does not occur on 2018.4.28f1, 2019.4.12f1, 2020.1.7f1, 2020.2.a11