Christine,
Depending on the model laptop you have there is function to toggle the display. Before trying the Computer 1/RGB, select the following sequence depending on your laptop model. (case# 241870)
Dell: [Fn] + F8
HP: [Fn] + F4
Toshiba: [Fn] + F5
Acer: [Fn] + F5
Gateway [Fn] + F4
Lenovo ThinkPad [Fn] + F7
MAC > Display> Arrangement > Detect Displays
Thanks!