private boolean isCurrentModelFlat() {
    boolean isFlat = true;
    Enumeration enumeration = getRoot().depthFirstEnumeration();

    while (isFlat && enumeration.hasMoreElements()) {
      isFlat = ((ChangesBrowserNode<?>)enumeration.nextElement()).getLevel() <= 1;
    }

    return isFlat;
  }
private boolean isCurrentModelFlat()