A system for a website building system includes at least one database storing website building system component types of websites of users, semantic composite types and smart box definitions where the semantic composite types are data structures describing components consisting of other components, a smart box handler to analyze and classify sets of components of a page of a website as smart boxes using semantic decomposition, the smart box boxes based on said semantic composite types and the smart box definitions, an editor to enable interactive editing of the website comprising components and the smart boxes, to receive a classification from the smart box handler and to provide additional editing capabilities for the smart boxes based on the classification.