title: Animating div on top of Highcharts very slow
body: <p>I am writing an app that uses Highcharts, and in one instance I want to have a "slider" at the bottom of the chart that extends up vertically over the chart. Moving the slider will update other parts of the page based on where the user moves the slider on the chart. </p>
  
  <p>The problem is that when drawing anything on top of the Highchart (image or a div) the performance becomes absolutely unacceptable. The slider simply cannot keep up with the mouse movements <a href="http://jsfiddle.net/4ghhf/68/" rel="nofollow">See a jsfiddle here</a>. Note - this only happens when working with a large number of data points (which is absolutely unavoidable in my case).</p>
  
  <p>Is there anything that I can do, short of not drawing on top of the chart? </p>