7.1 / Powebuilder 4 update problem.

We have a powerbuilder "update row" maintenance screen which explicitly locks the corresponding row it wishes to update prior to data entry. This lock could last for a long time depending on the speed and generosity of the user!! This lock cause problems to other users who trip over it and get locked row errors. Is there any slick way to avoid locking this row and yet maintain concurrency? Is there an Informix pseudo column on the row, which could be exploited prior to update in order to detect that another user updated the row first? Any simple solutions to the problem would be gratefully received.