void setElementId(Element e, String id) {
if (e.id != null)
idMap.remove(e.id);
Element old = (Element) idMap.put(id, e);
ResourceRef ref = resource.getResourceRef();
XRef xref = ref.takeOverUnresolvedXRef(id);
if (xref != null) {
xref.targetElement = e;
}
e.id = id;
if (old != null) {