Event Dispatching Thread Problem

Hi to all,

I have built a simple AWT Applet for educational purposes.
I draw one rectangle. The user waits 1000 ms and then I draw a second one
and so on. Then rectangles are drawn totally.
I added 2 buttons go and stop so that the user could re-execute or stop the
animation.
However these buttons are unresponsive while the animation is being executed
evenif I created a separated thread so as not to block the EDT.
I provide the code below.
Any help or suggestion would be highly appreciated.

Thanks in advance
Thanasis
++++++++++++++++++++++++++++++++++++++++++++++++

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class StopThread extends Applet implements Runnable {

   Button btnGo, btnStop;
   Thread calcThread = null;

 public void init() {

      btnGo = new Button("go");
      btnStop = new Button("stop");
      add(btnGo);
      add(btnStop);
      btnGo.addActionListener(new goButtonClass());
      btnStop.addActionListener(new stopButtonClass());
   }//end init

 public void run() {
      repaint();
   }

public void paint(Graphics g) {
  for (int i=0;i<=9;i++) {

    int r1= (int)(Math.random()*255);
          int r2= (int)(Math.random()*255);
          int r3= (int)(Math.random()*255);
          g.setColor(new Color(r1,r2,r3));

       g.drawRect(5+3*i,15+15*i,100,50);

      try {
         calcThread.sleep(1000);
      }
      catch (InterruptedException e){
      }
  }//end for
}//end paint

//========inner class Listener goButtonClass=============================
class goButtonClass implements ActionListener {
  public void actionPerformed(ActionEvent e) {
     if(e.getActionCommand().equals("go")) {
       System.out.println("go");
         if (calcThread == null) {
            calcThread = new Thread(StopThread.this);
            calcThread.start();
         }
      }

   }
}
//========inner class Listener stopButtonClass=============================
class stopButtonClass implements ActionListener {
  public void actionPerformed(ActionEvent e) {
     System.out.println("stop!!");
         if(calcThread != null) {
            calcThread.stop();
            calcThread = null;
         }
  }
}

// end stopButtonClass

}//end APPLET