After you lock your session then attempt to log back in and use SuperNova, there is no magnification or colour schemes available.
This was a known issue on Windows Server 2016 and Citrix XenApp 7.15.
NOTE: The issue has been fixed in the latest version of SuperNova.
If you have a relevant Software maintenance agreement you will be able to update automatically by checking for updates in-app or by downloading the latest version from our downloads page.