title: Knockout js registerEvent handler
body: <p>I'm having a great time playing around with knockout js and have just started to get to grips with adding custom bindingHandlers. </p>
  
  <p>I'm struggling a bit with the update function of a 3rd party jqWidget gauge - I can only get it to animate the first time I update the variable. On each update after that it just sets the value directly. </p>
  
  <p>I don't fully understand ko.utils.registerEventHandler() and what it does although I've seen it in a bunch of other examples. Is this what is causing the animation to break? How do I know which events to register from the 3rd party widget? </p>
  
  <p>For some reason this works fine if I add a jquery ui slider that is also bound to the observable.</p>
  
  <p>You can test this here: set the value a few times to see that it animates the first time and not after that. </p>
  
  <p><a href="http://jsfiddle.net/LkqTU/4531/" rel="nofollow">http://jsfiddle.net/LkqTU/4531/</a></p>