/**
* Append the object to the end of the parent's child list.
*/
public Object insertBefore(Object parent, Object index, Object newChild) {
ACSTreeNodeElement parentNode =
(ACSTreeNodeElement) parent;
ACSTreeNodeElement indexNode =
(ACSTreeNodeElement) index;
ACSTreeNodeElement newChildNode =
(ACSTreeNodeElement) newChild;
ACSTreeNodeElement clone =
(ACSTreeNodeElement) newChildNode.cloneNode(true);
parentNode.insertBefore(clone, indexNode);
ElementTreeModel model = (ElementTreeModel)_tree.getModel();
model.fireNodeChanged(parentNode);