If the displayed Items take more than one Page the Sorting only works on the displayed Items. But as a User i want to sort over all pages. E.g: Let there be a column with Persons, then i want to Sort to see, what has been created by John Doe. It is now very irritating, that John Doe is sorted next to Jane Doe on the first page but not all of their pages are displayed.

Whgen you now click on the Second page there are other Items of John and Jane Doe, but only the one which were there before.

As long as sorting does only affect the currently displayed subset (The displayed page), this feature is useless