title: How to center align Alert.show() in flex
body: <p>I have a tall Flex application that uses Alert.show( ) to display error/warning messages.  This created problems when the error messages were centered on the screen, but not visible when the screen was at an extreme scroll position (top or bottom). is there any way that i can display the Alert in the center of the user's viewable page. I've tried the following, but didn't work.</p>
  
  <pre><code>var errorMsg:Alert = Alert.show("Error message");
  PopUpManager.centerPopUp(errorMsg);
  </code></pre>
  
  <p>Thanks in advance.</p>