Removing unnecesarry usings problem

Hello.

I have this code:

https://image.prntscr.com/image/sGbpH00-Rwy8qxCikyWNDg.png

Ok, so I click Alt+Enter. The result is like this:

https://image.prntscr.com/image/_wdPQXxsSAOoFZpijnx8yw.png

Am I missing something or is it a bug? It's pretty annoying because I do a lot cross-namespace referencing in documentation (maybe it's a bad practice, but I just follow many folders so I have many related namesapces). And I like to get rid of all unused namespaces across the solution.