Scrollbars don't adapt after repopulating tree model

Question

Hello there,
I already post this question in the java programming forum since I didn't notice that the swing forum is here...
I designed a JFrame with Netbeans 6.1 having a JTree in a JScrollPane. The scrollbars work fine after initialization but when I remove and add nodes into the tree's model the scrollbars don't adapt. For instance when I expand all nodes I cannot scroll to the bottom leaf.
I tried to add and remove the nodes in two different ways:
* With add() and removeAll() from DefaultMutableTreeNode;
* With insertNodeInto() and removeNodeFrom from DefaultTreeModel
Both ways have the same result...
I guess I have to do something after I repopulate the model but I cannot figure out what.
Can anyone help?
Thanks,
Bart.

Answer 1

This works for me:
package tree;
* TreePopulateDemo.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
public class TreePopulateDemo extends JFrame {
    private DefaultTreeModel model;
    private JButton btInsert;
    private JButton btRemove;
    private JScrollPane jScrollPane1;
    private JToolBar jToolBar1;
    private JTree jTree1;
    public TreePopulateDemo() {
        super("TreePopulateDemo");
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(250, 150);
        setLocationRelativeTo(null);
        jScrollPane1 = new JScrollPane();
        jTree1 = new JTree();
        jToolBar1 = new JToolBar();
        btRemove = new JButton();
        btInsert = new JButton();
        jScrollPane1.setViewportView(jTree1);
        getContentPane().add(jScrollPane1, BorderLayout.CENTER);
        jToolBar1.setRollover(true);
        btRemove.setText("Remove");
        btRemove.setFocusable(false);
        btRemove.setHorizontalTextPosition(SwingConstants.CENTER);
        btRemove.setVerticalTextPosition(SwingConstants.BOTTOM);
        btRemove.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent evt) {
                MutableTreeNode node = getSelectedNode();
                if (node != null) {
                    model.removeNodeFromParent(node);
        jToolBar1.add(btRemove);
        btInsert.setText("Insert");
        btInsert.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent evt) {
                MutableTreeNode parent = getSelectedNode();
                if (parent != null) {
                    DefaultMutableTreeNode newChild = new DefaultMutableTreeNode("Test");
                    model.insertNodeInto(newChild, parent, parent.getChildCount());
        jToolBar1.add(btInsert);
        getContentPane().add(jToolBar1, BorderLayout.PAGE_START);
        model = (DefaultTreeModel) jTree1.getModel();
    private MutableTreeNode getSelectedNode() {
        MutableTreeNode node = (MutableTreeNode) jTree1.getLastSelectedPathComponent();
        if(node == null){
            JOptionPane.showMessageDialog(this, "Please select a node");
        return node;
    public static void main(final String args[]) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TreePopulateDemo().setVisible(true);
}