There is issue with ZorinOS core and the ICAclient of Citrix. The moment I install the ICAclient and reboot the system, the entire appearance of Zorin changes. Whether I use the ICAclient at a remote workplace or not. The problem already occurs if you have installed the ICAclient. Even if I use "sudo apt reinstall zorin-appearance zorin-appearance-layouts-shell-core zorin-appearance-layouts-support" it doesn´t bring back the appearence. After I deleted the ICAclient, Zorin looks the way I want it to.
I have also tested the ICAclient with POP_OS, Linux Mint, Ubuntu and Lubuntu and all of them do not have this problem.