@Override
  public ItemPresentation getPresentation() {
    return new DelegatingItemPresentation(super.getPresentation()) {
      @Override
      public String getLocationString() {
        if (!isValid()) {
          return null;
        }
        if (hasTrivialChildren()) {
          return super.getLocationString();
        }
        else {
          return null;
        }
      }
    };
  }
@Override
  public ItemPresentation getPresentation()