Test Studio would make changes to the project when the connection to TFS was lost. In order to reproduce the behavior:

1. Have a project in Test Studio connected and checked in TFS. 

2. Disconnect from the TFS (but not from Test Studio) break the connection.

3. Make any change to the project.

Expected behavior: You should be warned that the connection is lost and you should be offered to continue working offline or not make any changes.

Actual behavior: The changes are made on a project level.