How to reproduce:
1. Open the "IN-136542" project
2. In the Hierarchy window, create a new GameObject
3. Select the GameObject
4. In the Inspector window, click Add Component > BugDemoComponent
5. In the Inspector window, on the BugDemoComponent component, expand the "Foldout outside content container" Foldout
6. In the Hierarchy window, deselect the GameObject
7. In the Hierarchy window, select the GameObject again
8. Observe the Inspector window

Actual result: The "Foldout outside content container" Foldout is collapsed
Expected result: The "Foldout outside content container" Foldout remains expanded

Reproducible with: 2023.1.0a10, 6000.0.71f1, 6000.3.11f1, 6000.4.0f1, 6000.5.0a9, 6000.6.0a1

Reproducible on: macOS 26.3 (M1 Max)
Not reproducible on: No other environments tested

Workaround: Delete the “BugDemoInspector.cs” file and uncomment all code in “workaround.cs” file