I don't know if this has been posted yet, but when you have auto-hide enabled for the dock and you are in full-screen mode in an app (like safari), the dock will now stay hidden even if you move your mouse to the edge of the screen. This is new as of DP5 so far as I can tell. One thing worth nothing, if you Airplay Extend your desktop, the feature doesn't work anymore and moving your mouse to the edge of the screen will make the dock appear, even when in full-screen mode. So it looks like this feature has only been partially implemented. Nevertheless it's a nice little enhancement.