Facebook JavaScript SDK: FB.ui opens a popup window

I am trying to show a 'Post to Your Wall' feed dialog with the following code in a facebook iframe app:

<div id="fb-root"></div>
  <script src="http://connect.facebook.net/en_US/all.js">
  </script>
  <script>
     FB.init({ 
        appId:'249725835046216', cookie:true, 
        status:true, xfbml:true 
     });

     FB.ui({ method: 'feed', 
        message: 'Facebook for Websites is super-cool',
        name: 'Facebook Dialogs',
        link: 'http://developers.facebook.com/docs/reference/dialogs/',
        picture: 'http://fbrell.com/f8.jpg',
        caption: 'Reference Documentation',
        description: 'Dialogs provide a simple, consistent interface for applications to interface with users.'



        });
  </script>

The problem is that it is appearing in a new popup window like this:

Instead of appearing as like this without appearing in a popup window:

I don't want the feed dialog to appear in a new popup windows because in most modern web browsers where popups are blocked. I don't know why this is happening. Please help.