Regarding the xdt file. Does the ElementType ID="??" sequence matter? Does
<ElementType ID="21" content="eltOnly" history="F" name="descripGrp" order="many">
need to have a lower ID, than
<ElementType ID="22" content="mixed" name="descrip" order="many" type="string">
because descrip is a child of descripGrp?
Have you tested moving them around to see what happens? How are you creating the XDT? Should this be a question in the developers section? I think perhaps a little context would be useful and to know what you have already tried as this doesn't seem like a question arising from normal use of the software.
Dear Paul many thanks for your response.
We can close this question, sequential ordering is easier than testing non-sequential ordering.