Scroll Box not consuming mouse wheel at all?

So I was reading This Post

made about a month ago, talking about some issues he was having with his scroll box.
In his post, at step 7, he says he was able to get his scrollbar to consume his mouse wheel motions, verified by a print string. I am unable to replicate this.

My scrollbar works great otherwise its just the mouse wheel isnt consumed when I scroll within my scrollbox, not even when its set to always.