Autocomplete does not handle a source callback as expected

The documentation [says http://jqueryui.com/demos/autocomplete/] that a callback is accepted as a source.

However, if we simply pass a callback, autocomplete does not work. [Failure http://jsfiddle.net/vSdqE/2/].

If we call the callback ourselves and explicitly pass the array, then it works. [Success http://jsfiddle.net/vSdqE/1/].

Solution: callback should be called!