java中 按钮触发循环事件后 所有按钮都不响应了

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

public class ComplexLayouts extends MyFrame implements ActionListener
{
private static Button[] bt =new Button[6];
private static Panel p;
public ComplexLayouts(String str)
{
super(str);
}
/**
* @param args
*/
public static void main(String[] args)
{

// TODO 自动生成方法存根
ComplexLayouts cl = new ComplexLayouts("ComplexLayouts!");

p = new Panel();
p.setBackground(Color.lightGray);
p.add(bt[0]);
p.add(bt[1]);
cl.add(p,BorderLayout.NORTH);
cl.add(bt[2],BorderLayout.WEST);
cl.add(bt[3],BorderLayout.CENTER);

}
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == bt[3])
{
System.exit(0);
}
else
{
int i = 0;
while(true)
{
try
{
Thread.sleep(250);