This event occurs on the application footer display.
This event occurs on the application footer display, it is frequently used when it is required to display any calculated data on grids or report footer.
Ex:
sc_lookup(ret," select sum({item_value}) from orders_items where id_order='{fld_id_order}' ");
{fld_footer_total_field_a} = {ret[0][0]} * 0,1;
The field {fld_footer_total_field_a} must be created on fields menu