With Thisform .txtRoute.Value = this.value .txtRoute.refresh() .cRouteNo = this.value .cDirectn = this.List( this.ListIndex, 3) && Directn is 3rd in list .txtDirectn.value = .cDirectn .txtDirectn.refresh() .cmdPrint.enabled = .T. .cmdPreview.enabled = .T. EndWithHaving selected from the list box, the accompanying text box, .txtRoute, is assigned the value from the list box, taken from the select cursor/table. Now, whilst writing the form, I'd set its ControlSource to ROUTE.Route (its PK), but now I was "overwriting" it with the cursor's .Route (taken from select of the Route table). No immediate complaint from the form though, until I click the preview button. As I said in the orig message, the error was popping up somewhere between the two events, but not where it could be trapped. Strikes me that somewhere it should have said it didn't like it.