title: ie9: annoying pops-up while debugging: "Error: '__flash__removeCallback' is undefined"
body: <p>I am working on a asp.net mvc site that uses facebook social widgets. Whenever I launch the debugger (ie9 is the browser) I get many error popups with: Error: '__flash__removeCallback' is undefined.</p>
  
  <p>To verify that my code was not responsible I just created a brand new asp.net mvc site and hit F5.
  If you navigate to this url: <a href="http://developers.facebook.com/docs/guides/web/#plugins" rel="noreferrer">http://developers.facebook.com/docs/guides/web/#plugins</a> you will see the pop-ups appearing.</p>
  
  <p>When using other browsers the pop-up does not appear.
  I had been using the latest ie9 beta before updating to ie9 RTM yesterday and had not run into this issue.</p>
  
  <p>As you can imagine it is extremely annoying...
  How can I stop those popups?
  Can someone else reproduce this?</p>
  
  <p>Thank you! </p>