Anyone happen to see what I might be doing wrong. I'm trying to add
items to my

JComboBox on the fly as nodes are added to the tree. It's like this ...

1. User adds tree nodes to a tree.
2. Then user can select on another node elsewhere in the tree which
renders a JComboBox

and the items just added from step 1 are listed in this box.

I have a few problems ...
- after I select my item in the combobox, the combobox stays there. If
I then select on another node, the item in the combobox doesn't get
selected. It doesn't work where I just select an item and it closes up
and that item is selected.

- sometimes I get a null pointer exception in action performed (because
getSelectedIndex() in getCellEditorValue() returns a -1) which seems to
get called while the program execution is still in the
getTreeCellEditorComponent. This confuses me. Why's it returning -1
when there are items in my combobox?

Any help much appreciated.

(I hope I've got my code snippet here w/o any typos, I had to cut it
down)
----

public class TreeEditor extends AbstractCellEditor implements
TreeCellEditor
{
private JComboBox myComboBox;

public TreeEditor() {
    myComboBox = new JComboBox();

    myComboBox.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            TreePath path = jTree.getSelectionPath();

                  stopCellEditing();

                   Integer val = (Integer) getCellEditorValue();

                  myComboBox.setSelectedItem(val.intValue());

                   ((MyUserObjectInfo)nodeInfo).setName(
                         myComboBox.getSelectedItem().toString());

                   node.setUserObject(((MyUserObjectInfo) nodeInfo));
                   jTree.getModel().valueForPathChanged(path, nodeInfo);
        }
    });
}

public Object getCellEditorValue() {

    return new Integer(myComboBox.getSelectedIndex());
}

public Component getTreeCellEditorComponent(JTree tree,
    Object value, boolean isSelected, boolean expanded,
        boolean leaf, int row) {

    // find the children of this node that were recently added ...
    TreeModel tModel = jTree.getModel();
       Object root = tModel.getRoot();
       DefaultMutableTreeNode carRoot = (DefaultMutableTreeNode)
        tModel.getChild(root, 0);

       String nodeName = null;

       if (myComboBox.getItemCount() > 0) {
                myComboBox.removeAllItems();
       }

    // add children of another node into this combobox.
       for (Enumeration e = carRoot.children(); e.hasMoreElements();)
{
                DefaultMutableTreeNode carNode =

(DefaultMutableTreeNode)e.nextElement();
                  Object nodeInfo = carNode.getUserObject();
                  nodeName = ((MyUserObjectInfo)nodeInfo).getName();

                  myComboBox.addItem(nodeName);
       }

       if (myComboBox.getItemCount() > 0) {
                  myComboBox.setSelectedIndex(0);
       }

    return myComboBox;
}
}