Cannot apply css class to specific autocomplete elements

I was trying to apply a css class to a specific autocomplete list item to be able to mark which ones are special. I've noticed that any style changes that I try to apply within the _renderItem function are completely ignored. However, when I revert to a previous version of jQueryUI (such as 1.9.2), I notice that applying a css class or style in the _renderItem function works as expected. An example of this can be seen at http://jsfiddle.net/s7Sja/ .