static Component selectSubdirOrCreateNew(File motherDir, final VF1<File> action) {
  JList list = jlist(map f2s(listDirs(motherDir)));
  
  onDoubleClickOrEnter(list, voidfunc(S path) {
    callF(action, newFile(path));
    disposePIFrame(list);
  });
  
  ret showFrame_returnContents("Choose a directory", withCenteredButtons(
    withTitle("Please select a directory or create one", list),
    
    listDependentButton(list, "OK", r {
      callFInNewThread(action, newFile(selectedItem(list)));
      disposePIFrame(list);
    }),
    
    jbutton("Create directory...", r {
      inputText("Name of new directory", voidfunc(S name) {
        File f = mkdirs(newFile(motherDir, name));
        callFInNewThread(action, f);
        disposePIFrame(list);
      });
    })));
}