Windows 10 taskbar appears on top of session

Our costumer has got an windows 10 client pc and runs parallels client to connect to our server. The taskbar of the client appears on top of the the taskbar of the logged-in session on the server, I tried the following things:
- update of parallels client
- reinstall of parallels client but still the taskbar appears in front of the session

 

@MartijnD1:
What is the exact version of the parallels client that is being used?
Is more than one monitor being used?

 

@jpc
Parallels Client for Windows Version 16.5.1 (20448)
2 monitors are being used

 

Solved itself, probably had something to do with background processes

 

If that is so, then it could be related to some taskbar icon or tray icon.
https://www.howtogeek.com/howto/317...ndows-taskbar-refuses-to-auto-hide-correctly/