Dual monitor problem

I have a laptop that I usually connect to an external monitor. I use Ubuntu 16.04 and Gnome 3.18.5. When I do connect to the external monitor, I like to turn the laptop screen off. I can do that by going to System Settings, Screen Display, selecting the built-in display and then clicking "off".

Dual monitor problem

I have a laptop that I usually connect to an external monitor. I use Ubuntu 16.04 and Gnome 3.18.5. When I do connect to the external monitor, I like to turn the laptop screen off. I can do that by going to System Settings, Screen Display, selecting the built-in display and then clicking "off".