Possible documentation error?

[John Haugeland]

>From the lists module documentation for ukeysort/2:

"Returns a list containing the sorted elements of the list TupleList1 where
all but the first tuple of the tuples comparing equal have been deleted."

Actual behavior is to make unique on key equality, not on tuple equality.

243> lists:ukeysort(2, [ {1,1}, {2,1}, {2,2} ]).
[{1,1},{2,2}]

Am I missing something obvious?