@Override
  public final void update(@NotNull AnActionEvent e) {
    FileChooserPanel panel;
    FileSystemTree tree;
    if ((panel = e.getData(FileChooserPanel.DATA_KEY)) != null) {
      e.getPresentation().setEnabled(true);
      update(panel, e);
    }
    else if ((tree = e.getData(FileSystemTree.DATA_KEY)) != null) {
      e.getPresentation().setEnabled(true);
      update(tree, e);
    }
    else {
      e.getPresentation().setEnabledAndVisible(false);
    }
  }
@Override
  public final void update(@NotNull AnActionEvent e)