Making Desktop 2 in Mountain Lion be shown in external display Is it possible to display Desktop 2 (Mountain Lion) in an external display?

The thing is I want to use Full Screen applications in an external display while using my Laptop display for non-full-screen applications.

With the Mirror Display unchecked, when I drag an application to the external display and set it to full screen, my laptop display goes black.
I have been using an external display for a little while and was confused about this to begin with.  I think it happens when you have a particular window on full screen.  That is to say that it is the extended display version of having a single window to the fore.  I started dragging windows to size manually and it stopped happening.