activate.bs.scrollspy not being called with a dropdown?

Created by: matchew

I have this Table of Contents in a dropdown and I want to use scrollspy() to keep track of where I am in the document. I often have hundreds of pages so a dropdown with and `overflow-y: auto;`` makes some design sense at this point. However, I also would like to do some other things when the page changes. Notably Change Page # on the dropdown button to the actual page. According to the documentation I would use something like the following:

$('#myScrollspy').on('activate.bs.scrollspy', function () {
  // do something…
});

however, this fails to work. see the following fiddle: http://jsfiddle.net/2W8AC/