Computer-implemented methods for allowing users to specify interactive graphical designs are provided. The graphical designs can comprise multiple dimension versions—such as a tablet dimension version or a phone dimension version. Some of the methods involve an inheritance structure that defines a first dimension version of the design as a child of a second dimension version of the design. Specifications for properties of widgets in the graphical design are applied to the design in accordance with the inheritance specification. Some of the methods involve an inheritance characterization that determines how properties of a widget are affected by the inheritance structure across different dimension versions. Some of the methods involve an existence property for the widgets.