title: 1120: Access of undefined property startButton
body: <p>What am i doing wrong?
  the startButton is a button and inside a movieclip (menuScreen)
  the instancename of the button is startButton.</p>
  
  <p>Line 12    1120: Access of undefined property startButton.
   Line 13    1120: Access of undefined property startButton</p>
  
  <pre><code>package 
  {
  import flash.display.MovieClip;
  import flash.display.SimpleButton;
  import flash.events.MouseEvent;
  
  public class MenuScreen extends MovieClip 
  {
      var startButton:StartButton;
      public function MenuScreen();
      {
          startButton = new StartButton();
          startButton.addEventListener( MouseEvent.CLICK, onClickStart );
      }
  
      public function onClickStart( event:MouseEvent ):void
      {
          dispatchEvent( new NavigationEvent( NavigationEvent.START ) );
      }
  }
  }
  </code></pre>