DISABLE LANGUAGE BAR POPUP

Hello everyon,

im using a thirdy-party rdp app, from this app i can make the user logon the server opening only the ERP (Application) who i want they uses. All other things like desktop, and other are disable, the user ONLY sees the application. But they still can see a popup language bar, and this makes they reachs controll pannel if they want. 

We dont have azure directory.

Thats the bar i want to remove.