9. The computer-implemented process of claim 1 wherein a user can modify alternate versions of content and wherein said user modifications will modify said tree data structure.
9. The computer-implemented process of claim 1 wherein a user can modify alternate versions of content and wherein said user modifications will modify said tree data structure. 10. The computer-implemented process of claim 9 wherein modifying the alternate versions of content modifies the tree data structure by at least one of the following: deleting a version of document content will delete an OR node associated with said document content from said tree data structure; copying a version of alternate content will duplicate said copied version of alternate version as a sub-tree to the document tree; and copying a version of alternate content by using a special copy operation will copy a selected region of alternate content but not preserve its underlying structure in the document tree.