How to reproduce:
1. Open the “Unity6Test” project
2. Open the “New Shader Graph” as a floating window (Assets → Scenes)
3. Right-click in the empty space of the Shader Graph
4. Select the Create Node option in the context menu
5. Close the Shader Graph window
6. Observe the Editor and the Console

Expected result: Shader Graph closes with the Create Node Menu and no error appears
Actual result: Create Node Menu stays and “NullReferenceException: Object reference not set to an instance of an object” appears

Reproducible in: 2023.1.0b1, 6000.0.24f1, 6000.1.0a1
Not reproducible in: 2021.3.45f1, 2022.3.51f1, 2023.1.0a26

Reproducible on: Windows 10
Not reproducible on: No other environment tested