title: onbeforechange callback for intro.js
body: <p>I've got a callback function written for the onbeforechange method.  Below is the code:</p>
  
  <pre><code>introJs().onbeforechange(function() {
      if($(this).is(":visible") != true)
          if($(this).is("ui-tabs-panel") == true)
              $('.ui-tabs-nav a[href$="' + $(this).attr('id') + '"]').click();
          else
              $(this).show();
  }).start();
  </code></pre>
  
  <p>The logic is correct (tested without calling introJs().start()) however, this callback function still doesn't get called before the next step.  Any ideas?</p>