RT 3.8.1 - search ordering preferences doesn't work?

HI all,
I am new to this list, though I have done some experience
using/customizing RT in the past weeks.

I have a problem that I have been unable to solve, and for which I have
not found suggestions on the wiki or the mailing list archives:

the user “search preferences” let me choose the sorting of the results,
but I haven’t been able to make it work. Whatever field/order I select,
I always get the search results in ascending ID order. Do you see this