How do I setup dual monitors in XFCE/Xubuntu?

First, open up monitor config - it's in Start > Settings > Settings Manger, then open the Displayitem.

Make sure both your displays are on.enter image description here

Then, open a terminal and run this:

xrandr

The output will look something like this:

`Screen 0: minimum 320 x 200, current 2464 x 900, maximum 4096 x 4096 LVDS1 connected 1024x600+1440+0 (normal left inverted right x axis y axis) 220mm x 129mm 1024x600 60.0*+ 65.0800x600 60.3 56.2640x480 59.9VGA1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 408mm x 255mm 1440x900 59.9*+ 75.01280x1024 75.0 60.01280x960 60.01280x800 74.9 59.81152x864 75.01024x768 75.1 70.1 60.0832x624 74.6800x600 72.2 75.0 60.3 56.2640x480 72.8 75.0 66.7 60.0

720x400 70.1

`

Then, run the following, changing VGA1 and LVDS1 to match the appropriate display:

xrandr --output VGA1 --left-of LVDS1

Note that you can move change --left-of to --right-of.

Now, it should work, but you've still got one problem.

It will disappear after you logout. So, you need to add it to your login items.

Head over to Start > Settings > Settings Manger, then open "Session and Startup", add the above command to your login items, and you're good to go!