Before following these directions you may need to have xrandr 1.5.0, the first version to have virtual displays.
-
Use
xrandrto get a list of displays(xrandr -q) as well as of monitors(xrandr --listmonitorsor--listactivemonitors). In this scenario my up2414q showed up as two panels, DP-1-8 and DP-1-9 -
Create a virtual display with them in order to have them functionally work as one display
xrandr --setmonitor 24inch auto DP-1-8,DP-1-9
More documentation on xrandr, beyond just manpages, can be found here: http://www.straightrunning.com/tools/xrandr.html#sect3