Shadowing a remote session from within Parallels Remote Application Server Console requires user confirmation although the following GPO:
Administrative Templates > Windows components > Remote Desktop Services > Remote Session Host > Connections: “Set rules for remote control of Remote Desktop Services user sessions”.
has been set to Full Control without user's permission.
Parallels Remote Application Server checks GPO during Terminal Server Agent status check. Terminal Agent status should be rechecked to apply the GPO changes.
To update Terminal Server Agent status in Remote Application Server Console navigate to Farm > Terminal Servers > right-click Terminal Server > Check Agent.