this is one-to-many form, the items are entered in the detail form.

I use buffering=5

eg:

01001  10 pcs
01002  20 pcs
01001  10 pcs

it works fine when the cashier enters the items.

but if the cashier moves the cursors up and down, the message always show up.

I need a code to detect the double items, not itself.

thanks for the help.