Instead of relying only on the column's group_operator, ensure the view itself asks for the aggregation function (by checking if the corresponding field attribute is set). If the @group_operator function is not set on the field (even without a label, it just has to be *there* so `<field sum=""/>` would work), do not aggregate the column at all. bzr revid: xmo@openerp.com-20111114081853-a9ja0zdaxk2261nd