9. The computer-readable medium of claim 8, wherein: the layout further comprises a plurality of components, each component comprising a plurality of the objects; each object having an associated identifier and an associated instance code; the layout further comprises a plurality format groups, each format group comprising a plurality of the object identifiers that are used in a plurality of the components; and the step of retrieving the propagation rule for the first object property comprises the steps of, determining whether the first object property is a format property; if the first object property is a format property, identifying a particular one of the format groups that is associated with the first object, and retrieving a propagation rule associated with the format group that is associated with the first object.
8. The computer-readable medium of claim 1, wherein: the layout further comprises a plurality of components, each component comprising a plurality of the objects; each object having an associated identifier and an associated instance code; the layout further comprises a plurality content groups, each content group comprising a plurality of the object identifiers that are used in a plurality of the components; and the step of retrieving the propagation rule for the first object property comprises the steps of, determining whether the first object property is a content property; if the first object property is a content property, identifying a particular one of the content groups that is associated with the first object, and retrieving a propagation rule associated with the content group that is associated with the first object.