This example allows you to switch the three provided skins: Default, Monochrome and Custom.

To set a skin you need to use the "Skin" property to "Default", "Monochrome" or Custom".  To modify an existing skin or make a new one by altering/creating the respective CSS and image files in the  ~ /RadControls/Spell/Skins folder.  The skins follow the convention of describing the appearance in a CSS stylesheet, called Dialogs.css.  The images that the stylesheet references are placed in the CssImg subfolder.

Developers also can also customize dialog layout and appearance. The dialogs' files are in the directory ./RadControls/Spell/Dialogs, more precisely in the Controls subdirectory.
Important: Please, note that although you can rearrange the elements of the dialog, you need to include all elements when designing your custom skin.

If you experience some discrepancies in the skin visualization when migrating from IE6 to IE7, visit the knowledge base article below along with the resource linked at the bottom of it:
Migration from IE6 to IE7