Comment 13 for bug 986967

The code is:

    private void authentication_complete_cb ()
    {
        bool is_authenticated;
        if (test_mode)
            is_authenticated = test_is_authenticated;
        else
            is_authenticated = greeter.is_authenticated;

        if (is_authenticated)
        {
            /* Login immediately if prompted */
            if (prompted)
            {
                user_list.login_complete ();
                if (!test_mode)
                {
                    if (user_list.background.alpha == 1.0)
                        start_session ();
                    else
                        user_list.background.notify["alpha"].connect (background_loaded_cb);
                }

I wonder if the background is not completely loaded at this point and there's a problem there?