Context sensitive suggestions don't seem to work with Named Graphs

[Stiksels]

The following query shows all 40 predicates from the full dataset as suggestion

SELECT *
WHERE {
  GRAPH ?metadataGraph {
    ?concept <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2004/02/skos/core#Concept> .
    ?concept  
  }
}

By removing the GRAPH clause, the context sensitive suggestions are correct:

SELECT *
WHERE {
    ?concept <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2004/02/skos/core#Concept> .
    ?concept  
}