void ShowRootMaps() {
  TObjArray *oa = gInterpreter->GetRootMapFiles();
  TIter i(oa);
  TObject *o;
  TNamed *n;
  TString s;
  while ((o = i.Next()) != NULL) {
    n = dynamic_cast<TNamed *>(o);
    Printf("%-40s --> %s", n->GetName(), n->GetTitle());
  }
}