Bug: Mark Read on scroll

At least, I consider this a bug… :). It seems the scroll out of view trigger fires no matter which direction you scroll, and I think it should be only when scrolling posts ‘up’ off the top of the view.

For example, scroll a post until you can just see the first line of its title then scroll it off the bottom again. It will be marked as read when in fact you’ve only seen a few pixels of it.