Ubuntu – KDE – Displays only shows monitor or laptop screen, not both


I have a Carbon X1 running Ubuntu 19.04 with KDE Plasma 5. When colleagues also running KDE plug an external monitor in, System Settings -> Display and Monitor will show all the displays. Mine however only show one box, even though the Primary Display dropdown lists No Primary Output, Laptop Screen and U28D590 (HDM1). This seems to mean I can mirror my output on both screens, but nothing else.

enter image description here

How do I get both displays to appear, so I can arrange them, and display different out on each.

Best Answer

When multiple monitors display the same content, have the same resolution and are not unified, they are stacked exactly on top of each other in the GUI. Just drag the monitor in front to the side to reveal the other monitor(s):

enter image description here

Related Question