diff --git a/addons/sale/sale_view.xml b/addons/sale/sale_view.xml
index 9a59b2dad44..9925354346b 100644
--- a/addons/sale/sale_view.xml
+++ b/addons/sale/sale_view.xml
@@ -223,7 +223,7 @@
                                 <field name="incoterm" widget="selection"/>
                                 <field name="picking_policy" required="True"/>
                                 <field name="order_policy" on_change="shipping_policy_change(order_policy)"/>
-                                <field name="invoice_quantity" attrs="{'readonly':[('order_policy','=','prepaid'),('order_policy','=','picking')]}"/>
+                                <field name="invoice_quantity" attrs="{'readonly':[('order_policy','in',('prepaid','picking'))]}"/>
                             </group>
                             <group colspan="2" col="2">
                                 <separator string="References" colspan="2"/>