I discovered an interesting scenario recently. Although “Enable column sorting in dashboards” was checked (turned on), I was unable to sort on a particular table.  The mouse icon changed when I moused-over the column headings which gave the impression that it would sort, but it simply did not work.

Turns out there was an invalid “view” above the Table object in the Compound Layout. This happens when an object is removed from an analysis/request and its placeholder is not removed from the Compound Layout. See the screenshot below – notice the empty placeholder above the table with the message “The view that was in this position the the Compound Layout is no longer available. …”.

To fix the problem, simply remove/delete that invalid view from the compound layout and you will now be able to sort the table.