11:15 < annevk> a more complicated check might be not allowing referencing a 
                <datalist> child unless the <label> is itself a child of the 
                same <datalist>
11:15 < hsivonen> annevk: I found another type=hidden bug while I was at it. 
                  thanks
11:15  * hsivonen has totally forgotten about datalist
11:16 < hsivonen> why would labels refer to datalists?
11:16 < annevk> <label for=x> ... </label> <datalist> <select id=x> </select> 
                </datalist>
11:16 < hsivonen> eww.
11:17 < annevk> the conforming case would be <datalist> <label for=x> </label> 
                <select id=x> </select> </datalist>