To achieve what you want you need to edit this GPO :
https://admx.help/?Category=Windows_10_2016&Policy=Microsoft.Policies.TerminalServer::TS_RemoteControl_2



Open Gpedit with Administrator rights

Go to Windows Components > Remote Desktop Services > Remote Desktop Session Host > Connections > Set rules for remote control of Remote Desktop Services user sessions


Once you are on  "Set rules for remote control of Remote Desktop Services user sessions",

set this GPO at 2 : Full Control without user's permission

or at 4 : View Session without user's permission

(we believe that you probably want 2)


Then also modify the file "AppControl.ini" located in "C:\program files (x86)\tsplus\userdesktop\files

and add under [Security] this line:  "sessionsmanager-showconsentprompt = no"

Once done, when you will click in the AdminTool> Sessions Manager on the "Remote Control" button, 

TSplus will ask Windows to take control of the session without displaying a confirmation prompt to the user.


However, modifying the .ini is not enough, the GPO must also be configured 

(and a reboot will be mandatory for the GPO to be taken into account).