Nice little viewer. It needs a small fix in the initialization of Win_XML code replace "XMLDocument("XML",sCont)" with the code below to be warned when a document is not strict XML. That is it looks like XML but isn't true XML.
bNresult is boolean = XMLDocument("XML",sCont)
IF bNresult = False THEN
Info(ErrorInfo(errFullDetails))
Close(MyWindow)
END