JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/moment.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/fullcalendar/2.4.0/fullcalendar.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/fullcalendar/2.4.0/fullcalendar.js"></script>
<div id='wrap'>

  <div id='external-events'>
    <div id='external-events-listing'>
      <h4>Draggable Events</h4>
      <div class='fc-event' data-color="#FF0000" style="background-color:red">My Event 1</div>
      <div class='fc-event' data-color="#00FF00" style="background-color:green">My Event 2</div>
 
    </div>
    <p>
      <input type='checkbox' id='drop-remove' checked='checked' />
      <label for='drop-remove'>remove after drop</label>
    </p>
  </div>

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

  <div style='clear:both'></div>

</div>

CSS

body {
  margin-top: 40px;
  text-align: center;
  font-size: 14px;
  font-family: "Lucida Grande", Helvetica, Arial, Verdana, sans-serif;
}

#wrap {
  width: 1100px;
  margin: 0 auto;
}

#external-events {
  float: left;
  width: 150px;
  padding: 0 10px;
  border: 1px solid #ccc;
  background: #eee;
  text-align: left;
}

#external-events h4 {
  font-size: 16px;
  margin-top: 0;
  padding-top: 1em;
}

#external-events .fc-event {
  margin: 10px 0;
  cursor: pointer;
}

#external-events p {
  margin: 1.5em 0;
  font-size: 11px;
  color: #666;
}

#external-events p input {
  margin: 0;
  vertical-align: middle;
}

#calendar {
  float: right;
  width: 900px;
}

JavaScript

$(document).ready(function() {


  /* initialize the external events
  -----------------------------------------------------------------*/

  $('#external-events .fc-event').each(function() {

    // store data so the calendar knows to render an event upon drop
    $(this).data('event', {
      title: $.trim($(this).text()), // use the element's text as the event title
      stick: true // maintain when user navigates (see docs on the renderEvent method)
    });

    // make the event draggable using jQuery UI
    $(this).draggable({
      zIndex: 999,
      revert: true, // will cause the event to go back to its
      revertDuration: 0 //  original position after the drag
    });

  });


  /* initialize the calendar
  -----------------------------------------------------------------*/
	var myColor;
  $('#calendar').fullCalendar({
    header: {
      left: 'prev,next today',
      center: 'title',
      right: 'month,agendaWeek,agendaDay'
    },
    editable: true,
    droppable: true, // this allows things to be dropped onto the calendar
    dragRevertDuration: 0,
    drop: function( date, jsEvent, ui, resourceId) {
      // is the "remove after drop" checkbox checked?
      if ($('#drop-remove').is(':checked')) {
        // if so, remove the element from the "Draggable Events" list
        $(this).remove();
      }
      myColor = $(this).data("color");
      console.log(myColor);
      jsEvent.eventColor = myColor;
      /* alert(myColor) */
    },
    eventColor:myColor,
    eventDragStop: function(event, jsEvent, ui, view) {

      if (isEventOverDiv(jsEvent.clientX, jsEvent.clientY)) {
        $('#calendar').fullCalendar('removeEvents', event._id);
        var el = $("<div class='' data-color='"+myColor+"' >").css({'background-color':+myColor}).appendTo('#external-events-listing').text(event.title);
        el.draggable({
          zIndex: 999,
          revert: true,
          revertDuration: 0
        });
        el.data('event', {
          title:...