Get rid of second display

I have been using two monitors, and at one point I went to the 'Change the appearance of your displays' in the 'Screen Resolution' dialog, and added another display by clicking on a button. But now I can't get rid of it, and it seems to be causing problems. Now sometimes the pc boots with that screen size. It is the laptop screen size, that option. Nothing happens when I right click it, there doesn't seem to be any way of getting rid of it, help much appreciated.

Found it!

The answer for anyone struggling with the same thing is that 'remove this display' is an option in the last pulldown menu.