static L dm_windows_filterOnTitle(final F1<S, Bool> f) {
  ret [O w : dm_windows() | callF(f, getString(w, 'windowTitle))];
}

static L dm_windows_filterOnTitle(final IF1<S, Bool> f) {
  ret [O w : dm_windows() | callF(f, getString(w, 'windowTitle))];
}