title: FullCalendar (jQuery) refetchEvent won't show events
body: <p>I used to have </p>
  
  <pre><code>$('#calendar').fullCalendar({
      //some properties...
      events: "/Agenda/GetEvents/",
  });
  </code></pre>
  
  <p>It worked fine and my event showed correctly. Now I want to update the events (refetch) on a combobox selection, so here's what I changed:</p>
  
  <pre><code>$('#calendar').fullCalendar({
      //some properties...
      events: function (start, end) {
          $.ajax({
              url: '/Agenda/GetEvents/',
              dataType: 'json',
              data: {
                  start: Math.round(start.getTime() / 1000),
                  end: Math.round(end.getTime() / 1000),
                  utilisateur: $("#Utilisateur option:selected").val()
              }
          });
          $('#Calendar').fullCalendar('refetchEvents');
      },
  });
  </code></pre>
  
  <p>The url at /Agenda/GetEvents/ gets called correctly and returns one event, but it won't show on the calendar anymore. Am I doing something wrong?</p>