private void ensureParentsVisible(){
  Set<Object> parentNodes=new HashSet<Object>();
  for (  Object node : visibleNodes) {
    Object parentNode=parentProvider.getParent(node);
    while (parentNode != null) {
      parentNodes.add(parentNode);
      parentNode=parentProvider.getParent(parentNode);
    }
  }
  visibleNodes.addAll(parentNodes);
}

private void ensureParentsVisible ( ) { Set < Object > parentNodes = new HashSet < Object > ( ) ; for ( Object node : visibleNodes ) { Object parentNode = parentProvider . getParent ( node ) ; while ( parentNode != null ) { parentNodes . add ( parentNode ) ; parentNode = parentProvider . getParent ( parentNode ) ; } } visibleNodes . addAll ( parentNodes ) ; }
sets all parents of the visible nodes visible .
