Extended desktop using XFCE

In the XFCE display settings manager, if you see your screen but instead of extending the desktop it clones the desktop on both displays.

To enable this. use xrandr
You should see something like this

LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 310mm x 174mm

blahblah

HDMI1 connected 1280x720+1366+0 (normal left inverted right x axis y axis) 16mm x 9mm

To extend the desktop and use the HDMI connected monitor on the right side, do this:

➜  ~  xrandr --output HDMI1 --right-of LVDS1