title: The calendar is black on pageload but works of i click the next day
body: <p>I have a fullcalendar that is loaded in a div in a webpage. when the page loads, it has all its buttons but there are no grid to display the days, its just no space. </p>
  
  <p>however, if i click next/prev or any of the buttons the calendar is show properly.</p>
  
  <p>ive tried to spesificly load today:</p>
  
  <pre><code>$('#userboxCalendar').fullCalendar('today');
  </code></pre>
  
  <p>but it does not work :( any idea?</p>