When you are switching between the Sessions the used Kit from the old Session is used, instead of the Kit that the Session used the last time.

-> Steps to reproduce.

 1.) Open a new Session and open an example Project, use Default Kit for the Project
       for example GCC 64Bit

 2.) Open a new Session and open the same Project but this time select a different Kit for the
       Project, for example Android

3.) Open the first Session again, the saved Kit is now Android instead of GCC 64Bit.