How to reproduce:
1. Create a new project
2. Add an empty GameObject to the scene and add an Audio Source component
3. Click on the "3D Sound Settings" text to expand the sound settings.
4. It does not expand.

Only when clicking specifically on the tiny arrow does it expand. This does not match the behavior of other components, for example the "Animations" list on the Animation component, or "Materials" on the Mesh Renderer component.