Yup I definitely tried to click them a couple times... they don't fad away for me in Chrome, they just disappear, left me wondering if I needed to play some sort of game to get to them properly.
Also, looking at the ::selection example, it should mentioned that it's not safe to group vendor prefixes in the selector portion of a declaration block, as, unlike with properties, the whole block will be skipped if an unrecognized selector is encountered by a UA's CSS parser.