Change JPanel background after its been set once

[mevets]

I am trying to change the background color of my JPanel inside of my applet on button press. I have tried panel.setBackground(Color.GREEN). But nothing changes, so I figured I had to add repaint(), but still nothing.

In my example I havent added a button handler much, but you can see the p11.setBackground() in the NewJApplet class at the end of init.

How can I successfully change the backgrounds of my JPanels?

import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.JApplet;
import javax.swing.JButton;

public class NewJApplet extends JApplet {
    public void init() {
        setLayout(new GridLayout(3, 2));
        PaintPanel p11 = new PaintPanel();
        PaintPanel p21 = new PaintPanel();
        PaintPanel p12 = new PaintPanel();
        PaintPanel p22 = new PaintPanel();

        JButton reset = new JButton("Reset");
        JButton quit = new JButton("Quit");

        add(p11);
        add(p21);
        add(p12);
        add(p22);
        add(reset);
        add(quit);
        p11.setBackground(Color.BLUE);
        p11.repaint();
        repaint();
    }
}

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JApplet;
import javax.swing.JComponent;
import javax.swing.JPanel;

public class PaintPanel extends JPanel {
    protected PaintPanel() {
        super();
        setBackground(Color.GRAY);
    }

    protected void paintComponent(Graphics g) {
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(Color.GRAY);
        g2d.fillRect(0, 0, 250, 250);
        g2d.setColor(Color.RED);
        g2d.fillRect(50, 50, 50, 50);

    }
}

[Michael Dunn]

first thing to try is to add the usual suspects:

protected void paintComponent(Graphics g) {
        super.paintComponent(g);//<----------------
        Graphics2D g2d = (Graphics2D) g;

[mevets]

I added that and still the panel is still not changing its background

[Michael Dunn]

did you close your browser (totally) between changes?

[mevets]

Thanks I was using chrome and I guess restarting that browser fixed the problem. I also did not need those repaint() methods.