How to reproduce:
1. Open any new project
2. Go to Window -> Text -> Font Asset Creator and dock it
3. Go to Window -> TextMeshPro -> Font Asset Creator and dock it
4. Go to “Layouts” and choose any layout
5. Observe the Console
Actual result: “Callback unregistration failed. Callback not registered.” error is thrown and text disappears in Hierarchy window
Expected result: No errors appear in the Console and text does not disappear in Hierarchy window
Reproducible with: 6000.0.0f1, 6000.0.77f1, 6000.3.17f1, 6000.4.11f1, 6000.5.0b12, 6000.6.0a7
Reproducible on: macOS 15.7.5 (by user), Windows 11
Not reproducible on: No other environments tested