public Prob13Runner(){//constructor

    setDefaultCloseOperation(
                           WindowConstants.EXIT_ON_CLOSE);

    controlPanel.setLayout(new GridLayout(2,1));
    controlPanel.add(colorPanel);
    controlPanel.add(buttonPanel);

    colorPanel.setBackground(Color.GREEN);
    colorPanel.add(new JLabel("Red = "));
    colorPanel.add(redField);
    colorPanel.add(new JLabel(" Green = "));
    colorPanel.add(greenField);
    colorPanel.add(new JLabel(" Blue = "));
    colorPanel.add(blueField);
    colorPanel.add(colorIndicatorPanel);

    colorIndicatorPanel.setBorder(
                           new LineBorder(Color.black,1));
    colorIndicatorPanel.setPreferredSize(
                                    new Dimension(20,20));