Permission dialog on Facebook iframe app not closing after accept

Question

Hello there

I'm writing an iframe app from which I need to update user wall status. First I place a fb:login-button, which opens a popup asking user to login in Facebook. after loging in the callback takes the app to a page where the user is asked to grant permissions.

I'm using this code to get permission for offline access and status updates:

  FB.ensureInit(function(){
    FB.Connect.showPermissionDialog('offline_access,status_update', function(accepted) { window.close(); } );
  });

The dialog shows and the user can accept the permissions, everything works fine, but the dialog box won't close. It remains open, in white colour, and you have to close it from the corner button (not the popup, but the dialog inside). Then the whole popup closes (as it is said in the window.close() call).

Any clues?

Thanks in advance!