public static final boolean DEFAULT_BUFFER_USED = false;

    /** The default panel width. */
    public static final int DEFAULT_WIDTH = 680;

    /** The default panel height. */
    public static final int DEFAULT_HEIGHT = 420;

    /** The default limit below which chart scaling kicks in. */
    public static final int DEFAULT_MINIMUM_DRAW_WIDTH = 300;

    /** The default limit below which chart scaling kicks in. */
    public static final int DEFAULT_MINIMUM_DRAW_HEIGHT = 200;

    /** The default limit below which chart scaling kicks in. */
    public static final int DEFAULT_MAXIMUM_DRAW_WIDTH = 800;

    /** The default limit below which chart scaling kicks in. */
    public static final int DEFAULT_MAXIMUM_DRAW_HEIGHT = 600;

    /** The minimum size required to perform a zoom on a rectangle */
    public static final int DEFAULT_ZOOM_TRIGGER_DISTANCE = 10;

    /** Properties action command. */
    public static final String PROPERTIES_COMMAND = "PROPERTIES";

    /** Save action command. */
    public static final String SAVE_COMMAND = "SAVE";

    /** Print action command. */
    public static final String PRINT_COMMAND = "PRINT";

    /** Zoom in (both axes) action command. */
    public static final String ZOOM_IN_BOTH_COMMAND = "ZOOM_IN_BOTH";

    /** Zoom in (domain axis only) action command. */
    public static final String ZOOM_IN_DOMAIN_COMMAND = "ZOOM_IN_DOMAIN";

    /** Zoom in (range axis only) action command. */
    public static final String ZOOM_IN_RANGE_COMMAND = "ZOOM_IN_RANGE";

    /** Zoom out (both axes) action command. */
    public static final String ZOOM_OUT_BOTH_COMMAND = "ZOOM_OUT_BOTH";

    /** Zoom out (domain axis only) action command. */
    public static final String ZOOM_OUT_DOMAIN_COMMAND = "ZOOM_DOMAIN_BOTH";

    /** Zoom out (range axis only) action command. */
    public static final String ZOOM_OUT_RANGE_COMMAND = "ZOOM_RANGE_BOTH";

    /** Zoom reset (both axes) action command. */
    public static final String ZOOM_RESET_BOTH_COMMAND = "ZOOM_RESET_BOTH";

    /** Zoom reset (domain axis only) action command. */
    public static final String ZOOM_RESET_DOMAIN_COMMAND = "ZOOM_RESET_DOMAIN";

    /** Zoom reset (range axis only) action command. */
    public static final String ZOOM_RESET_RANGE_COMMAND = "ZOOM_RESET_RANGE";

    /** The chart that is displayed in the panel. */
    private JFreeChart chart;

    /** Storage for registered (chart) mouse listeners. */
    private transient EventListenerList chartMouseListeners;