I have a problem with the following code.  The code is supposed to create a
new node and add it as a child to another node in a JTree.  This is indeed
happening but the tree is only updating the display and selecting the new
node the first time a node is added.  For each subsequent child node, it
appears as though the child node is added successfully but it is just not
appearing in the tree.  If I check getChildCount() on the parent node after
each child is added it reveals the correct number so it seems to be a
display issue.  Could someone please point out the mistake in the following
code?

This code exists in a control class (not in the JTree itself).  The variable
parentNode is a DefaultMutableTreeNode passed in as a parameter:

DefaultMutableTreeNode childNode = new DefaultMutableTreeNode();
parentNode.add(childNode);
tree.setSelectionPath(new TreePath(childNode.getPath()));
MyTreeModel model = (MyTreeModel)tree.getModel();
model.nodesWereInserted(parentNode, new int[] {parentNode.getChildCount() -
1});
tree.repaint();

This is the tree model:

public class MyTreeModel extends DefaultTreeModel
{
  private DefaultMutableTreeNode root;
  private ArrayList<TreeModelListener> listeners = new
ArrayList<TreeModelListener>();

  public MyTreeModel(DefaultMutableTreeNode root)
  {
     super(root);
     this.root = root;
  }

  public void addTreeModelListener(TreeModelListener l)
  {
     listeners.add(l);
  }

  public Object getChild(Object parent, int index)
  {
     return ((DefaultMutableTreeNode)parent).getChildAt(index);
  }

  public int getChildCount(Object parent)
  {
     return ((DefaultMutableTreeNode)parent).getChildCount();
  }

  public int getIndexOfChild(Object parent, Object child)
  {
     return
((DefaultMutableTreeNode)parent).getIndex((DefaultMutableTreeNode)child);
  }

  public Object getRoot()
  {
     return root;
  }

  public boolean isLeaf(Object node)
  {
     return ((DefaultMutableTreeNode)node).isLeaf();
  }

  public void removeTreeModelListener(TreeModelListener l)
  {
     listeners.remove(l);
  }

  public void valueForPathChanged(TreePath path, Object newValue)
  {
  }
}