Drop user & login error: Cannot drop user because it does not exist or you do not have permission. (4285397)

Dropping a user then a login from the "Drop Login" window (Object Explorer | Server Security | Logins) results in the following error: 

"Cannot drop the user because it does not exist or you do not have permission."

After the error is thrown, the Drop Login window will still show the user.

WORKAROUND:

In the backend, Toad does drop the user and the login.  Refreshing the Object Explorer will show that the user and login is not there.  It seems that the Drop Login GUI at the time of drop throws the correct error message by mistake and does not refresh itself.

STATUS:

This issue was fixed in Toad for SQL Server 6.1.  The latest version of Toad can be downloaded at: https://support.quest.com/