static JComboBox jcomboboxFromConcepts_str(Class<? extends Concept> cc) {
  ret jcomboboxFromConcepts_str(db_mainConcepts(), cc);
}

static JComboBox jcomboboxFromConcepts_str(Concepts concepts, Class<? extends Concept> cc, Concept selected default null) {
  L<S> items = ll("");
  S selectedItem = null;
  for (Concept c : list(concepts, cc)) {
    S item = c.id + " - " + c;
    if (c == selected) selectedItem = item;
    items.add(item);
  }
  ret jcombobox(items, selectedItem);
}