Thank you for this information... and a thank you too much if you arrive to fix it ... because I have doing the crazy man ... and I push directly the new XOOPS core in my production site !!!
(I've never had problem with a XOOPS upgrade...)
And in french country there is other people who have the same problem !!!
For now I back them with the information you gave me part.
So I wait hoping you could find a patch Trabis? you think it's feasible?