“InvalidCastException” errors are thrown and the Inspector becomes empty/greyed out when a Data Source Type is selected and unset

Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Create a UI Toolkit Visual Element in the Hierarchy (UI Toolkit > Standard Elements > Visual Element)
3. Enter editing stage
4. Select "Type" under the Bindings in the Inspector
5. Click the "Select Type..." button and choose any type
6. Click the burger button and select "Unset" or "Unset All"
7. Unselect the Visual Element in the Hierarchy by clicking on an empty space
8. Select the Visual Element in the Hierarchy
9. Observe the Inspector and the Console windows

Actual results: “InvalidCastException” errors are thrown and the Inspector becomes empty/greyed out

Expected results: No errors are thrown and the Inspector is still functional

Reproducible with versions: 6000.6.0b6, 6000.7.0a3

Can’t test with versions: 6000.0.0f1, 6000.0.80f1, 6000.3.21f1, 6000.5.6f1 (due to no editing stage feature)

Tested on (OS): MacOS Silicon Tahoe 26.5.1, Windows 11

Notes:

• Does not reproduce in the UI Builder