Center a fixed draggable div

I have a fixed div which I am trying to center vertically and horizontally. Yes, I know there are many question and tutorials to perform this. I checked and followed the instructions. Here's one that I implemented:

#draggable {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

Now, I also want the div to be draggable. So it should start off at the center of the screen, then the user will have an option to drag it.

The problem is, when you start dragging it, the div suddenly moves higher. How can I center a fixed, draggable div?

JSFiddle

$('#draggable').draggable();

body {
  width: 2000px;
  height: 2000px;
  background-image: url("http://www.freevector.com/site_media/preview_images/FreeVector-Square-Patterns-Set.jpg");
}
#draggable {
  background-color: red;
  color: lightblue;
  width: 200px;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

<script type="text/javascript" src="//code.jquery.com/jquery-2.1.4.js"></script>
<script type="text/javascript" src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
<link rel="stylesheet" type="text/css" href="//code.jquery.com/ui/1.11.4/themes/ui-lightness/jquery-ui.css">

<div id="draggable">Drag Me!</div>

Edit I updated the examples. draggable doesn't have a set height.

You could use draggable start method to modify css.

$('#draggable').draggable({ start: function() {

$(this).css({transform: "none", top: $(this).offset().top+"px", left:$(this).offset().left+"px"});

} });

http://jsfiddle.net/y2ehtjsu/4/

This gets current position calculated by browser and converts it into normal pixel value, on draggable start. If you are using draggable I sugggest you to familiarize yourself with this: http://api.jqueryui.com/draggable/