<?xml version="1.0"?>
<data><xpath expr="//field[@name='partner_id']" position="after">
                <field name="sale_line_id" optional="hide" readonly="1"/>
                <field name="allow_billable" column_invisible="True"/>
            </xpath>
            <xpath expr="//field[@name='partner_id']" position="attributes">
                <attribute name="invisible">not allow_billable</attribute>
            </xpath>
        </data>