An Appearance object that holds a collection of skins.
Use the Add method to add or replace skins to the control.
The skin method, in it's simplest form, uses a single graphic file (*.ebn)
assigned to a part of the control. By using a collection of objects laid over
the graphic, it is possible to define which sections of the graphic will be
used as borders, corners and other possible elements, fixing them to their
proper position regardless of the size of the part.