JDialog preferred size is not big enough

Hello,

i 'have a JDialog with "lots" of JComponent in it. I would like to set
the size of the JDialog with the preferred size of itself, but it
doesn't work (the preferred height seems too small). here is a sample code.

I guess i must add some height, but which one?

import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class TestPreferred extends JDialog {

    private JPanel jContentPane = null;
    private JPanel jPanel = null;
    private JButton jbOk = null;
    private JButton jbCancel = null;
    private JPanel jPanel1 = null;
    private JLabel jLabel = null;
    private JComboBox jComboBox = null;
    private JSlider jSlider = null;
    private JTextField jTextField = null;
    private JCheckBox jCheckBox = null;
    private JCheckBox jCheckBox1 = null;

    public TestPreferred(Frame owner) {
        super(owner);
        initialize();

        setSize(getPreferredSize());
    }

    private JPanel getJPanel() {
        if (jPanel == null) {
            jPanel = new JPanel();
            jPanel.setLayout(new GridBagLayout());
            jPanel.add(getJbOk(), new GridBagConstraints());
            jPanel.add(getJbCancel(), new GridBagConstraints());
            dumpSizes("jPanel", jPanel);
        }
        return jPanel;
    }

    private JButton getJbOk() {
        if (jbOk == null) {
            jbOk = new JButton();
            jbOk.setText("OK");
            dumpSizes("jButton", jbOk);
        }
        return jbOk;
    }

    private JButton getJbCancel() {
        if (jbCancel == null) {
            jbCancel = new JButton();
            jbCancel.setText("Cancel");
            dumpSizes("jButton1", jbCancel);
        }
        return jbCancel;
    }

    private JPanel getJPanel1() {
        if (jPanel1 == null) {
            GridBagConstraints gridBagConstraints5 = new GridBagConstraints();
            gridBagConstraints5.gridx = 1;
            gridBagConstraints5.gridy = 4;
            GridBagConstraints gridBagConstraints4 = new GridBagConstraints();
            gridBagConstraints4.gridx = 1;
            gridBagConstraints4.gridy = 3;
            GridBagConstraints gridBagConstraints3 = new GridBagConstraints();
            gridBagConstraints3.fill = GridBagConstraints.VERTICAL;
            gridBagConstraints3.gridy = 2;
            gridBagConstraints3.weightx = 1.0;
            gridBagConstraints3.gridx = 1;
            GridBagConstraints gridBagConstraints2 = new GridBagConstraints();
            gridBagConstraints2.fill = GridBagConstraints.VERTICAL;
            gridBagConstraints2.gridy = 1;
            gridBagConstraints2.weightx = 1.0;
            gridBagConstraints2.gridx = 1;
            GridBagConstraints gridBagConstraints1 = new GridBagConstraints();
            gridBagConstraints1.fill = GridBagConstraints.VERTICAL;
            gridBagConstraints1.gridy = 0;
            gridBagConstraints1.weightx = 1.0;
            gridBagConstraints1.gridx = 1;
            GridBagConstraints gridBagConstraints = new GridBagConstraints();
            gridBagConstraints.gridx = 0;
            gridBagConstraints.gridy = 0;
            jLabel = new JLabel();
            jLabel.setText("JLabel");
            jPanel1 = new JPanel();
            jPanel1.setLayout(new GridBagLayout());
            jPanel1.add(jLabel, gridBagConstraints);
            jPanel1.add(getJComboBox(), gridBagConstraints1);
            jPanel1.add(getJSlider(), gridBagConstraints2);
            jPanel1.add(getJTextField(), gridBagConstraints3);
            jPanel1.add(getJCheckBox(), gridBagConstraints4);
            jPanel1.add(getJCheckBox1(), gridBagConstraints5);
            dumpSizes("jPanel1", jPanel1);
        }
        return jPanel1;
    }

    private JComboBox getJComboBox() {
        if (jComboBox == null) {
            jComboBox = new JComboBox();
        }
        return jComboBox;
    }

    private JSlider getJSlider() {
        if (jSlider == null) {
            jSlider = new JSlider();
        }
        return jSlider;
    }

    private JTextField getJTextField() {
        if (jTextField == null) {
            jTextField = new JTextField();
            jTextField.setColumns(20);
        }
        return jTextField;
    }

    private JCheckBox getJCheckBox() {
        if (jCheckBox == null) {
            jCheckBox = new JCheckBox();
            jCheckBox.setText("check1");
        }
        return jCheckBox;
    }

    private JCheckBox getJCheckBox1() {
        if (jCheckBox1 == null) {
            jCheckBox1 = new JCheckBox();
            jCheckBox1.setText("check2");
        }
        return jCheckBox1;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new TestPreferred(null).setVisible(true);
            }
        });
    }

    private void initialize() {
        this.setContentPane(getJContentPane());
    }

    private JPanel getJContentPane() {
        if (jContentPane == null) {
            jContentPane = new JPanel();
            jContentPane.setLayout(new BorderLayout());
            jContentPane.add(getJPanel(), BorderLayout.SOUTH);
            jContentPane.add(getJPanel1(), BorderLayout.CENTER);
            dumpSizes("ContentPane", jContentPane);
        }
        return jContentPane;
    }

    private void dumpSizes(String name, JComponent jcomp) {
        System.err.println(name + " : pref size = " + jcomp.getPreferredSize());
    }

}