To reproduce:
1. Create a new project
2. Select any game object
3. In the inspector Add Component > any new script
4. Open the script and change class name to anything and save
5. Go back to Unity and observe as the name of the script changed to the name of the game object
6. Open the script
7. Change the class name back to the original

Expected result: the name of the script is changed and no errors in the console
Actual result: Editor UI gets corrupted and nonstop NullReference exceptions are thrown in the console

Reproduced on: 2018.1.0b9 2018.1.0b11
Not reproduced on: 2017.3.1p4 2018.1.0b1 2018.1.0b5

Notes:
Workaround: press any other game object and the errors stop and UI is fixed.

On 2018.2.0a5 no errors are thrown and the UI works fine, but the script is missing until any other game object is selected