title: Flex PopupManager Issue
body: <p>I have been working with pop-up manager lately and have an inconsistency issue. </p>
  
  <p>This is created at application level, and then various levels are added to the application 
  requiring the pop-up to be brought to the front.  </p>
  
  <p>roughly 1 in 5 times the grayish haze will appear (which renders the application unusable) as with any pop-ups, but doesn't display my pop-up window. </p>
  
  <p>This is done within the component that i am popping-up and the application is the component that the pop-up is created on.  </p>
  
  <pre><code>PopUpManager.addPopUp(this,application,true);
  PopUpManager.bringToFront(this);
  PopUpManager.centerPopUp(this); 
  </code></pre>
  
  <p>Any clue how i can remove this inconsistency?</p>