Patent ID: 7308647

Claim:
A system comprising: a markup language core engine for providing categories of behaviors including layout and rendering behaviors; at least one external component designed to provide categories of external component behaviors including at least one of an external component layout behavior and an external component rendering behavior in addition to the behaviors provided by the core engine, wherein the external component layout behavior and the external component rendering behavior are one of an attached behavior or an element behavior; a pair of interfaces associated with each external component for communication between the external component and the core engine; a mechanism included in the core engine to extend a selected category of behavior of the core engine with the behaviors of a same category of the at least one external component, such that the behaviors of the same category of the at least one external component participate with the behaviors of the core engine, wherein the mechanism and the at least one external component communicate through the pair of interfaces to confirm participation, and participation includes the at least one external component delegating a portion that is less than all of a processing of the behaviors of the same category to the core engine; and an output medium to render and layout visual elements as a result of the participation among the markup language core engine and the at least one external component.