>in my case, I already created the blank record, so it doesn't work.
>
>every time the cashiers finish one item, it automatically create a new blank record, so the cashiers can work smoothly (don't have to click Add new button)
>
>is there any other way?

Do you mean you created and saved this new blank record?

Alternative way may be to try to detect lastkey() and if it's up/down arrow, don't fire validation.