To add some things...

When you have scrolling set to more than one line at a time, the item movement skips down multiple spots at a time. For example, when I click pick and scroll down once, it jumps down two spots (One moves to between Three and Four).

When I clicked Pick, it wasn't obvious to me what I was doing next. At first, I scrolled and didn't even notice it moved. I think the post I'm replying to includes changes that would remove that issue, so I'm mostly just re-iterating the idea that it needs more obvious clues as to what's going on.

Very cool, though