[Issue] Where did they originate from? (Attribute/Model Group)

References,

[1] http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Oct/0222.html
(member only)
[2] http://www.w3.org/TR/2003/WD-xmlschema-ref-20030109/#issue_mg_dups
[3] http://www.w3.org/TR/2003/WD-xmlschema-ref-20030109/#issue_ag_dups

Mary and I bumped into this issue. Today, there is no mechanism to trace
back the origin of some of the components that were assembled via compiling
an attribute/model group.

<quote>
(4) Unrolled named model and attribute groups
     Model groups and attribute groups get unrolled at the point of use in a
     way that leaves no trace in the component model. The same schema
components
     therefore recur in the graph in undetectable ways. Given that the named
     model and attribute groups exist in their own right as schema
components,
     this is at least inconsistent with how, say, type or attribute
declarations
     function and complicates rules for eliminating duplicate SCDs.
</quote>

For details, please refer to [1], [2] and [3].

Regards,

Asir