I have been stumped with this problem for days.
The JPanel does not update the JLabel component into the new JButton.
Even if the JButton is a new JLabel, the panel doesn't update.
Any help a million times appreciated.  thanks

import java.awt.BorderLayout;

import javax.swing.JComponent;
import javax.swing.JPanel;

public class Test extends JPanel {

    private JComponent display;

    public Test() {
        setLayout(new BorderLayout());

        display = createDisplay();
        if(display != null)
            add(display, BorderLayout.WEST);
    }

    public void setDisplay(JComponent display) {
        this.display = display;
        revalidate();
        repaint();
    }

    protected JComponent createDisplay() {
        return new javax.swing.JLabel("JLabel");
    }

    // Test code.

    public static void main(String[] args) {
        javax.swing.JFrame frame = new javax.swing.JFrame();

frame.setSize(java.awt.Toolkit.getDefaultToolkit().getScreenSize());
        frame.setVisible(true);

        Test test = new Test();
        frame.add(test, BorderLayout.SOUTH);

        test.setDisplay(new javax.swing.JButton("JButton"));
    }
}