title: How to detect if user previously authorized rights to a tabbed application without showing the authorization dialog?
body: <p>How can you detect if a user previously authorized a tab application, without showing the user an authorization dialog? This is a user experience concern. We don't want to throw the user at an authorization dialog without a call-to-action, but we don't want a call to action to be shown to log the user in if the user previously authorized the app.</p>
  
  <p>Here's the scenario. A tab application is hosted on a page that has several other applications. <strong>In Facebook, the 'Like' button does not work at the tab level but on a page level, so a user may have liked a different application without having seen the current application.</strong> Therefore, if any 'Like gate' is used on the landing page of a tab application, and authorization is required to use the app, then when we log the user in the user will be immediately shown the authorization screen without a call to action, unless we can detect that the user previously authorized this application.</p>