title: Trying to get a tooltip shown in eventRender from the fullcalendar documentation
body: <p>Im working on a fullCalendar overview interface Using: Flask-python on server and html jinja2 js on client side.</p>
  
  <p>Right now i am trying to create a tooltip on hover or click using tooltip.js.</p>
  
  <p>I have a bug that drives me to the popper.js index.</p>
  
  <p>here is my basic js:</p>
  
  <pre><code> document.addEventListener('DOMContentLoaded', function() {
      var calendarEl = document.getElementById('calendar');
  
      var calendar = new FullCalendar.Calendar(calendarEl, {
              plugins: ['dayGrid'],
              defaultView: 'dayGridMonth',
  
              eventRender: function(info) {
               var tooltip = new Tooltip(info.el, {
                      title: "info.event.extendedProps.description",
                      placement: 'top',
                      trigger: 'hover',
                      container: 'body'
                    });
          },
          events: {{hour}}           
  
      });
  
      calendar.render();
  
    });
  </code></pre>
  
  <p>From what i saw, le eventRender is called, if i mouseover the tooltip div is created BUT i got this error:</p>
  
  <pre><code>Uncaught TypeError: a is not a constructor
  at g.value (index.js:246)
  at index.js:381
  </code></pre>
  
  <p>which is referencing this:</p>
  
  <pre><code>this.popperInstance = new Popper(
    reference,
    tooltipNode,
    this._popperOptions
  );
  </code></pre>