With the new Citrix Receiver version there’s always an tray icon vissible. When you want to disable this tray icon, you can following this steps.
1.) Create a new Registry Item
2.) Browse to HKEY_CURRENT_USER\Software\Citrix\Receiver
3.) Create a new REG_DWORD with the value 0 (zero)
Login to your desktop/laptop again and you’ll see that the Citrix Receiver tray icon is gone! 😉