FROM in subqueries causes error

[Olivier Dameron]

Dear Jena community,
   a FROM in a SPARQL subquery generates an error:
${JENA_HOME}/bin/sparql --data=data.trig 
--query=query-subQuery-namedGraph.rq
Encountered " "from" "FROM "" at line 7, column 5.
Was expecting one of:
    <IRIref> ...
...
I did not seen any specification that prevents it, and the query runs 
fine with virtuoso. Did I miss something or is it a bug?
Thank you
olivier


with query-subQuery-namedGraph.rq:
----------------------------------

PREFIX od: <http://www.univ-rennes1.fr/dameron/ontology/rdfTest/>

SELECT ?val
WHERE {
  {
    SELECT ?val
    FROM od:MyGraph
    WHERE {
      od:a od:MyRelation ?val .
    }
  }
}

and data.trig:
--------------

@prefix od: <http://www.univ-rennes1.fr/dameron/ontology/rdfTest/> .

od:a od:MyRelation od:b .

GRAPH od:MyGraph {
  od:a od:MyRelation od:c .
}