public boolean getHorizontalAxisTrace() {
        return this.horizontalAxisTrace;    
    }
    
    /**
     * A flag that controls trace lines on the horizontal axis.
     *
     * @param flag  <code>true</code> enables trace lines for the mouse
     *      pointer on the horizontal axis.
     */
    public void setHorizontalAxisTrace(boolean flag) {
        this.horizontalAxisTrace = flag;