Monobehaviour cannot be loaded in inspector.

2) How can we reproduce it using the example you attached.
1. Open the scene "TestScene".
2. Click on GameObject and look at the inspector. Notice that the "Test" script cannot be loaded.
3. Open the "Test" script and try to figure out what's causing it. I think it may have something to do with namespaces.

Present in 4.2.1 and 4.3