Change the listing order of the view controllers in Xcode storyboard

I'm just starting my first application using storyboards. I'm using Xcode 4.5 and iOS 6 SDK. I want to know how to change the order in which the controllers are listed in the Document Outline (panel to the left of the storyboard).

In the Document Outline, drag the orange view controller icon. As you do this you will see the blue horizontal insertion point appear between the grey boxes. Let go and the whole grey group box for the view controller will relocate.