JS Not Functioning as Intended

Question

I am using a jQuery plugin called Sticky Floating Box to have a div that floats but is contained within the other div. It appears to work however it doesn't stay within the containing div. I have looked over the scripts demo page but cannot figure out what I am doing wrong.

Here is the JS Initialize Code:

$(function() {
   jQuery('.addthis').stickyfloat('update',{ duration:0});
});

Here is a jsFiddle showing the issue.

HTML and CSS Below:

<div class="header"> HEADER </div>
 <div class="container"> 
  <div class="addthis">
    <!-- AddThis Button BEGIN -->
      <div class="addthis_toolbox addthis_floating_style addthis_32x32_style">
            <a class="addthis_button_facebook"></a>
            <a class="addthis_button_twitter"></a>
            <a class="addthis_button_google_plusone_share"></a>
            <a class="addthis_button_pinterest_share"></a>
            <a class="addthis_button_compact"></a>
            <a class="addthis_button_email"></a>
      </div>
      <script type="text/javascript" src="//s7.addthis.com/js/300/addthis_widget.js#pubid=undefined"></script>
      <!-- AddThis Button END -->
  </div>
  <p>ICONS SHOULD STAY <BR> WITHIN THIS GRAY BOX<p>
</div>
<div class="footer"> SHOULD NOT GO BELOW THIS LINE</div> 

.header{
width:400px;
background: #F00;
height:100px;
margin:0 auto;
}
.container{
position:relative;
height:400px;
width:400px;
margin:0 auto;
background: #999;
}
.footer{
height:700px;
width:400px;
background: #F0F;
margin:0 auto;
}
.addthis{
position:absolute;
top:0;
left:-50px;
}   

Answer 1

I had to do three things to get the jsFiddle to work properly:

stickyfloat function needs to be called after the page is ready (and remove the 'update' part).

jQuery(document).ready(function() {
    jQuery('.addthis').stickyfloat({ duration:0});
});

Add the following css rule:

.addthis_floating_style
{
    position:inherit !important;
}

Give the .addthis div an explicit height and width:

.addthis
{
    position:absolute;
    top:0;
    left:-50px;
    width :36px;
    height:222px;
}