Empty space in full calendar

Question

I am using Full Calendar and using slots to segment the day. In doing so, I end up with a large amount of empty space at the bottom of the calendar.

I have cut down from my application to reproduce on the basic sample from Full Calendar's website. You'll find the HTML below. You can see the large empty space beneath 7pm between there and the end of the page - that's what I want to remove.

$(document).ready(function() {

  $('#calendar').fullCalendar({
    droppable: true,
    editable: true,

    defaultView: 'agendaWeek',
    header: {
      left: 'prev,next today',
      center: 'title',
      right: 'month,agendaWeek,agendaDay,listWeek'
    },
    slotDuration: '4:00:00',
    minTime: '07:00:00',
    maxTime: '23:00:00',
    timezone: 'local',
    allDaySlot: false,


    header: {
      left: 'prev,next today',
      center: 'title',
      right: 'month,basicWeek,basicDay'
    },
    defaultDate: '2018-03-12',
    navLinks: true, // can click day/week names to navigate views
    editable: true,
    eventLimit: true, // allow "more" link when too many events
    events: [{
        title: 'All Day Event',
        start: '2018-03-01'
      },
      {
        title: 'Long Event',
        start: '2018-03-07',
        end: '2018-03-10'
      },
      {
        id: 999,
        title: 'Repeating Event',
        start: '2018-03-09T16:00:00'
      },
      {
        id: 999,
        title: 'Repeating Event',
        start: '2018-03-16T16:00:00'
      },
      {
        title: 'Conference',
        start: '2018-03-11',
        end: '2018-03-13'
      },
      {
        title: 'Meeting',
        start: '2018-03-12T10:30:00',
        end: '2018-03-12T12:30:00'
      },
      {
        title: 'Lunch',
        start: '2018-03-12T12:00:00'
      },
      {
        title: 'Meeting',
        start: '2018-03-12T14:30:00'
      },
      {
        title: 'Happy Hour',
        start: '2018-03-12T17:30:00'
      },
      {
        title: 'Dinner',
        start: '2018-03-12T20:00:00'
      },
      {
        title: 'Birthday Party',
        start: '2018-03-13T07:00:00'
      },
      {
        title: 'Click for Google',
        url: 'http://google.com/',
        start: '2018-03-28'
      }
    ]
  });

});

body {
  margin: 40px 10px;
  padding: 0;
  font-family: "Lucida Grande", Helvetica, Arial, Verdana, sans-serif;
  font-size: 14px;
}

#calendar {
  max-width: 900px;
  margin: 0 auto;
}

<link href='https://cdnjs.cloudflare.com/ajax/libs/fullcalendar/3.9.0/fullcalendar.css' rel='stylesheet' />
<script src='https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.min.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/fullcalendar/3.9.0/fullcalendar.js'></script>


<div id='calendar'></div>