in the first or third screenshot, do you see the icon next to the object area icon? That allows you to define the interface area/border.
Quick question: did you add an image via the main properties tab for the interface? It can be a transparent .png, but it has to be the actual size that you want the interface to be. The background image controls the actual size & position of the interface.
Not defining the interface area means all of the interface will be visible, so it's up to you whether you want to define that.
P.S: I should have noticed that you hadn't linked a background image to the properties tab. D'oh! Scenes, menus & interfaces etc are all defined by their background image width & height.