Xref list editor

This is a specialized PSML fragment editor to add to, delete or reorganize a list of xrefs (cross-references).  Edits to the <xref-fragment> element invoke this editor. By default, the second fragment of a references document is configured to invoke the xref list editor. Adding an <xref-fragment> must be done through the PSML document template – there is no way to add one through the standard end-user interface.