This has been observed in T&Q vis a vis Section Info, but may apply to lots of tools - I'm not sure what the underlying issue is.
In Section Info, you can click on a table column title to sort (e.g. "Location") and then click on it again to reverse sort.
In T&Q, you can click on a column title to sort (e.g. "Last Modified" in Question Pools), but to reverse sort, you can only click on the up triangle next to the label.
This behaviour is therefore inconsistent across tools. The former is better, as in the latter case, there's a much smaller target area to click on and the sort / reverse sort actions are different.