Having trouble with nested JSplitPanes and am on a deadline...

Question

My demo code is pasted below. I tried to make it as close to my app environment as possible without making it too huge, it's already long enough as it is. Anyway, this should run without any imports needed and as a standalone. The problem is this: start the program, click "Hide Middle Panel". Then move the remaining divider over to the left a ways. Now click on "Show Middle Panel". Then action listener resets the right divider that was moved back to it's original location (desired), but even though it is setting the left divider to .5 after the right divider has been moved, it still uses the old width to determine the placement, so the result is that the left divider is out of place.
Is this a bug in JSplitPane? Or is it something I am doing wrong?
In my application, I have also written a similar handling of a resize event, which basically just sets the left divider to .5 again. When the split panes are in their invalid state, if I do nothing but resize slightly, the split panes right themselves. However, calling the method that is handling the resize event after setting the divider locations does not make a difference, nor does calling revalidate or repaint.
Thanks in advance,
Tonya
public class TestNestedSplitPane extends javax.swing.JFrame {
    /** Creates new form testNestedSplitPane */
    private TestNestedSplitPane() {
    public static TestNestedSplitPane instance() {
        if (null == instance) {
            instance = new TestNestedSplitPane();
            instance.initComponents();
        return instance;
    private void initComponents() {
        java.awt.GridBagConstraints gridBagConstraints;
        splitPaneContainerPanel = new javax.swing.JPanel();
        splitPaneContainerPanel.setPreferredSize(new java.awt.Dimension(500, 280));
        leftPanel = new javax.swing.JPanel();
        leftPanel.setBackground(java.awt.Color.BLUE);
        middlePanel = new javax.swing.JPanel();
        middlePanel.setBackground(java.awt.Color.GREEN);
        rightPanel = new javax.swing.JPanel();
        rightPanel.setBackground(java.awt.Color.RED);
        innerSplitPane = new javax.swing.JSplitPane(javax.swing.JSplitPane.HORIZONTAL_SPLIT, true, leftPanel, middlePanel);
        outerSplitPane = new javax.swing.JSplitPane(javax.swing.JSplitPane.HORIZONTAL_SPLIT, true, innerSplitPane, rightPanel);
        innerSplitPane.setDividerLocation(((int)splitPaneContainerPanel.getPreferredSize().getWidth()) * 1/3);
        outerSplitPane.setDividerLocation(((int)splitPaneContainerPanel.getPreferredSize().getWidth()) * 2/3);
        buttonContainerPanel = new javax.swing.JPanel();
        hideButton = new javax.swing.JButton();
        hideButton.addActionListener(OutsideListener.instance());
        getContentPane().setLayout(new java.awt.GridBagLayout());
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
        splitPaneContainerPanel.setLayout(new java.awt.BorderLayout());
        outerSplitPane.setContinuousLayout(true);
        outerSplitPane.setOneTouchExpandable(true);
        innerSplitPane.setContinuousLayout(true);
        innerSplitPane.setOneTouchExpandable(true);
        outerSplitPane.setLeftComponent(innerSplitPane);
        splitPaneContainerPanel.add(outerSplitPane, java.awt.BorderLayout.CENTER);
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.fill = java.awt.GridBagConstraints.BOTH;
        gridBagConstraints.weightx = 1.0;
        gridBagConstraints.weighty = 1.0;
        getContentPane().add(splitPaneContainerPanel, gridBagConstraints);
        hideButton.setText("Hide Middle Panel");
        buttonContainerPanel.add(hideButton);
        java.awt.Toolkit tk = java.awt.Toolkit.getDefaultToolkit();
        java.awt.Dimension d = tk.getScreenSize();
        setSize(500, 300);
        int screenHeight = d.height;
        int screenWidth = d.width;
        setLocation((screenWidth-500)/2, (screenHeight-300)/2);
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 1;
        gridBagConstraints.fill = java.awt.GridBagConstraints.BOTH;
        gridBagConstraints.weightx = 1.0;
        getContentPane().add(buttonContainerPanel, gridBagConstraints);
        pack();
    /** Exit the Application */
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
     * @param args the command line arguments
    public static void main(String args[]) {
        TestNestedSplitPane.instance().show();
    private static TestNestedSplitPane instance = null;
    public javax.swing.JButton hideButton = null;
    private javax.swing.JPanel splitPaneContainerPanel = null;
    private javax.swing.JPanel buttonContainerPanel = null;
    public javax.swing.JSplitPane outerSplitPane = null;
    public javax.swing.JSplitPane innerSplitPane = null;
    public javax.swing.JPanel leftPanel = null;
    public javax.swing.JPanel middlePanel = null;
    public javax.swing.JPanel rightPanel = null;
class OutsideListener implements java.awt.event.ActionListener {
    private static OutsideListener instance = null;
    private OutsideListener() {
    public static OutsideListener instance() {
        if (null == instance) {
            instance = new OutsideListener();
        return instance;
    public void actionPerformed(java.awt.event.ActionEvent e) {
        if (TestNestedSplitPane.instance().hideButton.getText().equalsIgnoreCase("Hide Middle Panel")) {
            TestNestedSplitPane.instance().middlePanel.setVisible(false);
            TestNestedSplitPane.instance().outerSplitPane.setDividerLocation(.67);
            TestNestedSplitPane.instance().hideButton.setText("Show Middle Panel");
        } else if (TestNestedSplitPane.instance().hideButton.getText().equalsIgnoreCase("Show Middle Panel")) {
            TestNestedSplitPane.instance().middlePanel.setVisible(true);
            TestNestedSplitPane.instance().outerSplitPane.setDividerLocation(.67);
            TestNestedSplitPane.instance().outerSplitPane.revalidate();
            TestNestedSplitPane.instance().innerSplitPane.setDividerLocation(.5);
            TestNestedSplitPane.instance().hideButton.setText("Hide Middle Panel");
}

Answer 1

However, I still get totally confused about the difference between validate() and revalidate().Same here. There seems to be no consistency. One combination of components will
respond to revalidate(), another combination will not.
Did you come across this solution by trying various combinations of validate(), revalidate(), repaint()?I (generally) find either revalidate() (on its own), or validate() and repaint() (combined) work
In this case, after spotting the revalidate(), validate()/repaint() was the first change I tried.
http://forum.java.sun.com/thread.jspa?threadID=583383Interesting discussion - I'll have bit more of a look through my swing books/notes and if I
find anything interesting I'll post back.