11. A method as claimed in claim 5 further synchronizing the Include File and the Support File at the end of the edit session, the steps comprising: updating changes to the Support File header fields that were made by the user, from a memory copy to a temporary copy to a permanent copy of the Support File; deleting data element cross-references in the memory copy of the Support File for which there is no corresponding data item in the Include File; updating changes to the data element cross-references that were made by the user, from the memory copy to the temporary copy to the permanent copy of the Support File.
5. A method as claimed in claim 4 further comprising the steps of: 5) creating a Support File corresponding to an Include File when the Include File initially created; 6) updating Support Files in response to screen based commands including copy, rename, delete, and move commands to maintain consistency; 7) synchronizing, at the end of an edit session, a Support File corresponding to the selected Include File to correspond to a latest version of the selected Include File.