Subform/combo-boxes

[rmdrye]

I have an order entry form where the main form is customer info and subform is in datasheet view bound to orders table. There is a GearName, GearSize, and StockNumber field. GearSize requeries GearName to show only sizes related to GearName selection and StockNumber automatically displays. I run into trouble adding multiple orders on the subform....when I go to make a selection on the next row of the datasheet, my combo box selctions erase the previous orders entered. The requery does not effect only the specific row. Could someone please help me with an expression or code to segregate the rows of the subform?