I think the problem is in js/autocomplete.js on lines 582-588
// TODO provide option to avoid setting focus again after selection? useful for cleanup-on-focus
More specifically the problem is the "return false" statement. If you remove that one it should work imho.
If an element (in this case the ul) has an onclick event that returns false the defeault behavior (in this case following the url that resides somewhere in this ul) is cancelled.