Steps to reproduce:
1. Create new Unity project using empty URP 3D Template
2. Open Package Manager window
3. Find and install ProBuilder package
4. Open Tools > Editors > Open Material Editor
5. Below the list press “Add”
6. Next to “Apply” button,  click the red square on the right edge of the button
7. Observe the Console window

Actual results: “GUI Error: Invalid GUILayout state in MaterialEditor view. Verify that all layout Begin/End calls match
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&) (at /Users/bokken/build/output/unity/unity/Modules/IMGUI/GUIUtility.cs:224)” error is thrown in the Console
Expected results: no errors are thrown in the Console

Reproducible with versions: 6.0.7 (6000.0.60f1, 6000.2.8f1, 6000.3.0b6 6000.4.0a2)

Tested on (OS): macOS Silicon, Tagoe 26.0 (M1)