Cognos Controller client - Excel behavior in Citrix session

When user inside Cognos Controller click on Reports - Run, Microsoft Excel pop’s up and Excel is put in front of Cognos Controller window.

How do you change the the excel behavior, so the cognos conntroller application windows stays in the front ?

Thanks

Details:
IBM Cognos Controller 10.4 on Windows 2012 R2 server with Office 365.

Hi All,
Do you know how to change the behavior.

Regards,
Martin