/** Continue to scroll to the left or right for every time step */
 public void actionPerformed(ActionEvent e) {
   if (directedToLeft) {
     wheeler.scrollLeft();
   } else {
     wheeler.scrollRight();
   }
 }
 /** Start the timer when the user presses the mouse. */
 public void mousePressed(MouseEvent e) {
   if (e.getSource().equals(left)) {
     directedToLeft = true;
     wheeler.scrollLeft();
     timer.start();
   } else if (e.getSource().equals(right)) {
     directedToLeft = false;
     wheeler.scrollRight();
     timer.start();
   } else if (e.getSource().equals(down)) {
     menu.show(down, 5, 5);
   }
 }