Hide unused icons from Dock
I have not tried it myself, but I read in a review that they intentionally made it harder to accidentally remove icons from the Dock.
Trying dragging the icon a good distance away from the dock and holding it there for a couple seconds, it should show you some kind of "about to poof this" indicator, and then drop it.
At least, that's what I got from the review I read.
I just noticed that if I right-click on these icons, there is a "Remove from Dock" hidden in the Options sub-menu in the context menu.