Elements fall into three categories, depending on their base class:
Layout elements derive from LayoutPanel. Each LayoutPanel arranges child items in a particular manner.
Painted elements derive from BasePrimitive. They override the OnPaint method to draw figures on the controls graphic surface.
Component elements derive from RadItem. RadItem descendants handle user input and can be used in the design environment. A component element overrides the virtual CreateChildElements method to create one or more layout elements and primitives. Typically TPF based controls are simple wrappers around RadItem descendant classes, and the RadItem descendant classes define logic and user interface. See the RadRadioButtonElement and RadTrackBarElement topics for examples.