Trying to create Netbeans Swing/GUI component

Question

Hello,
I'm trying to create a GUI component from the following code. The main idea is to create a component consisting of a checkbox and a panel. The panel can contain several other swing components. By checking or unchecking the checkbox I want all by components in the panel to be enabled or disabled.
The important thing is that this component should work in the Netbeans GUI designer. I'm using Netbeans 5.5.
My problem is the following:
When adding my swing component to the Netbeans swing component palette and dragging onto a new form, I cannot assign other components to the main panel of my component. Even if I use the Inspector tree to drag components to be children of my component, the mouse icon shows a denying icon.
If I add swing components programmatically, it works.
Can somebody give me an advice what I should change in my code to make it work with the Netbeans GUI designer?
Below you can find the current code of my standalone component. It includes a main() method so one can give it a try.
Many thanks in advance!
package test.swing;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JEnabler extends JPanel {
    private JCheckBox checkEnabler = new JCheckBox();
    private JPanel contentPane = new JPanel();
    public JEnabler() {
        super.setLayout(new BorderLayout());
        checkEnabler.setSelected(true);
        checkEnabler.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        checkEnabler.setMargin(new Insets(0, 0, 0, 0));
        checkEnabler.setVerticalAlignment(SwingConstants.TOP);
        checkEnabler.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                checkEnablerActionPerformed(evt);
        super.addImpl(checkEnabler, BorderLayout.WEST, -1);
        super.addImpl(contentPane, BorderLayout.CENTER, -1);
    private void checkEnablerActionPerformed(ActionEvent evt) {
        Component[] list = contentPane.getComponents();
        for (int i=0; i<list.length; i++)
            list.setEnabled(checkEnabler.isSelected());
protected void addImpl(Component comp, Object constraints, int index) {
contentPane.add(comp, constraints, index);
public LayoutManager getLayout() {
return contentPane.getLayout();
public void setLayout(LayoutManager mgr) {
if (contentPane!=null)
contentPane.setLayout(mgr);
public void remove(Component comp) {
contentPane.remove(comp);
public void remove(int index) {
contentPane.remove(index);
public void removeAll() {
contentPane.removeAll();
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JEnabler enabler = new JEnabler();
JTextField tf = new JTextField("Test");
enabler.add(tf);
JButton test = new JButton("Click");
enabler.add(test);
frame.getContentPane().add(enabler);
frame.pack();
frame.setVisible(true);

Answer 1

Can anyone tell me what I am missing?
public void paintComponents(Graphics g)you're not 'missing' anything, in fact you've gained an 's'