US Patent RE42509 Document processing to permit sharing of content by plural documents

A document processing apparatus which permits the sharing of a document element in a document structure while ensuring that any change to the content appears in the document element in each document sharing it. In a document processing apparatus for managing a plurality of documents each containing a plurality of document elements, a document element having content to be shared with a second document is designated from a plurality of document elements of a first document, and the content of the designated document element is defined as the content of a predetermined document element of the second document to be shared as common content by the first and second documents. Further, any document element having shared content is detected from a document when the display of the document is commanded, and is displayed in a distinguishable manner from other portions.