title: How to add a notification on the app tab of the Firefox?
body: <p>The FF4 delivers an app tab feature and it looks like both Gmail and Twitter have some notification code when a new mail or tweet come the app tab would look like a litter lighter.
  Does any know how to operate the app tab with the notification?
  I can see the code of a pinned application of IE9 with similar function. But I could not run into any document of FF.</p>