if (parent == null)
DefaultMutableTreeNode sibling = getNextSibling(); if (sibling != null) return sibling.getFirstLeaf();  if (parent != null) return ((DefaultMutableTreeNode) parent).getNextLeaf();
  public DefaultMutableTreeNode getNextLeaf()  {    if (parent == null)      return null;    // TODO: Fix implementation.    return null;    //return parent.getChildAfter(this);  }