- Add a script and attach it to any gameobject on the scene
- Open this script in MonoDevelop
- Refactor class name in the script to something else
(either Refactor -> Rename from context menu, or manually changing the name of the class and the script file name so that they match)
- Go back to the editor, click on the gameobject to which the script was attached to open Inspector window

Actual:
Previously attached script is now "Missing (Mono script)"

Expected:
The gameobject has the renamed script attached (works with Visual Studio)