static <A extends Concept> A conceptFromComboBox(JComboBox cb, Class<A> cc) {
  ret conceptFromComboBox(cb, mainConcepts, cc);
}

static <A extends Concept> A conceptFromComboBox(JComboBox cb, Concepts concepts, Class<A> cc) {
  S s = getTextFromComboBox(cb);
  if (empty(s)) null;
  long id = parseFirstLong(s);
  ret getConcept(concepts, cc, id);
}