On a fresh install of 18.04, with laptop and two external monitors, I turned off the laptop display in Settings->Devices->Screen Display using the ON/OFF slider. How do I turn it back on again? Once turned off, it is taken out of the display arrangement. If I remove the laptop from the dock and power-on, it's display works. If I hot plug into the dock again, the two external monitors switch on, but the laptop screen switches off.
2 Answers
You can turn it back on by clicking on your monitor number in the Display menu and selecting the monitor that is turned back off. Screengrab below: display monitor selection
Each monitor has a number. If you go to Settings > Devices > Screen Display
and find the monitor number that is your primary monitor. Click on the number and it will show you a dropdown menu of all available monitors. Select the one you turned off and turn it back on.
- Go to Settings
- Click on Devices
Now you should have a window like the one displayed Displays
Then click on the display button (below the Display Arrangement section -- in my case it is 'Dell 22"')
You will get a menu listing of all your displays. You can then select the display you want to enable and turn on the display.