If I understand the docs correctly, since the Santa example does NOT contain the NOSORT, shouldn't I be able to sort the data by clicking on any of the column headers (such as Occupation) ?
NOSORT only applies to initially adding the items to the list, and then they are sorted according to the first column. For any additional sorting, you'd have to do that yourself by installing a "Sort callback". I haven't really gotten around to documenting that. It's not particularly easy.