I've got a dual monitor host with Windows 10. At home I'm using the RU relay to connect to this work system. I also have a dual monitor setup at home. I've tried going to the RDP properties of the connection and enabling "Use all my monitors for the remote session", however the change does not persist (option is unchecked if I visit RU options again).
Could you please try the following steps and see if the properties are saved this way? 1. In the main Viewer window right-click on the connection entry and select Connection Properties. 2. In the Connection Properties window navigate to the RDP tab and click Configure to invoke the RDP configuration window. 3. In the RDP's client properties window navigate to the Display tab and enable the "Use all monitors" checkbox. 4. Navigate back to the General tab and click Save: 5. After this close the RDP's client configuration window and try reopening it later once again - the properties you've previously set should be saved.