Problem with menu

package pak;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.*;
 
public class MyMidlet extends MIDlet implements CommandListener{
 
public String ip;
public String port;
private Command exitCommand;
private Command connectCommand;
public Form form;
private Displayable current;
private Display display;
    MyCanvas myCanvas = new MyCanvas(this);
    public void startApp() {
    display=Display.getDisplay(this);
    if (current!=null)
      display.setCurrent(current);
    else{
      display.setCurrent(getForm());
      current=form;
    }
    }
 
    public void pauseApp() {
    }
 
    public void destroyApp(boolean unconditional) {
    }
 
    public Display getDisplay () {
        return Display.getDisplay(this);
    }
 
    public Form getForm(){
         form = new Form("My Form");
         form.addCommand(getExitCommand());
         form.addCommand(getConnectCommand());
         form.setCommandListener(this);
         return form;
    }
   public Command getExitCommand() {
        if (exitCommand == null) {
            exitCommand = new Command("Exit", Command.EXIT, 0);
        }
        return exitCommand;
    }
   public Command getConnectCommand() {
        if (connectCommand == null) {
            connectCommand = new Command("Connect", Command.ITEM, 0);
        }
        return connectCommand;
    }
   public void commandAction(Command c, Displayable d) {
        if (d == form) {
            if (c == exitCommand) {
               exitMIDlet() ;
            }
            else{
                if(c == connectCommand){
                   myCanvas.addCommand(getExitCommand());
                   myCanvas.setCommandListener(this);
         myCanvas.start();
        getDisplay().setCurrent(myCanvas);
 
                }
 }
           }
    }
   public void exitMIDlet() {
        switchDisplayable (null, null);
        destroyApp(true);
        notifyDestroyed();
    }
   public void switchDisplayable(Alert alert, Displayable nextDisplayable) {
        Display displa = getDisplay();
        if (alert == null) {
            displa.setCurrent(nextDisplayable);
        } else {
            displa.setCurrent(alert, nextDisplayable);
        }
    }
 
class MyCanvas extends GameCanvas implements Runnable {
 
    MyMidlet midlet;
    private boolean isRunning = true;
        private Graphics g;
    public MyCanvas(MyMidlet midlet){
        super(true);
        this.midlet = midlet;
    }
        public void start(){
 
        Thread runner = new Thread(this);
        runner.start();
    }
 
public void run(){
 
        g = getGraphics();
        flushGraphics();
 
        while (isRunning) {
            try{
        Thread.sleep(30);
            }
        catch(Exception ex){}
}//while is running
    }
}
}