I have noticed that the "Select Object"-Window in combination with the AssetsOnly attribute only works with fields of type GameObject and not MonoBehaviour scripts. Is that by design?
The following works fine:
[AssetsOnly] public GameObject test;
While this does not:
[AssetsOnly] public SomeMonoBehaviour test;
I can drag&drop the prefab onto the property, but I can not pick the prefab via the select window. The window is empty and only offers "None".
Unity: 2017.2.0f3 OS: Windows 10