As others have said, don't use a FILTER. One additional problem is that the scroll bar and scroll thumb on the grid won't work properly and will frustrate users.

>Set filter to works better than a relation when it comes
>to display only some itens of the child table
>
>eg.
>
>SET FILTER TO ALLTRIM(UPPER(FATHER_TABLE.type)) = ALLTRIM(UPPER(child_TABLE.type))
>
>I put the code into the roll_event of the grid, so it happens
>every time I move to a record on the grid of the father table
>
>I am wrong ? I am forcing the system ?