Setting Stage properties

The Stage class overrides most properties and methods of the DisplayObject class. If you call one of these overridden properties or methods, Flash Player and AIR throw an exception. For example, the Stage object does not have x or y properties, since its position is fixed as the main container for the application. The x and y properties refer to the position of a display object relative to its container, and since the Stage is not contained in another display object container, these properties do not apply.