I have two forms, both have optimistic buffering set in the dataenvironment, cursor buffering set to 5 for optimistic table buffering and multilocks set on in the load event of the form. In one I am using a comparison on curval(this.controlsource) and it works fine. In the other I get the error "Function requires row or table buffering mode". I know that I did something reasonably simple to get this working before but am drawing a blank. Any ideas?