diff --git a/product/ERP5/Document/TradeCondition.py b/product/ERP5/Document/TradeCondition.py
index de089cf2ad6217c470dc73a92a4741e18eb4babd..67e6cccb97e5c3ee8cbe387d9a26bbd306cc3446 100644
--- a/product/ERP5/Document/TradeCondition.py
+++ b/product/ERP5/Document/TradeCondition.py
@@ -70,6 +70,9 @@ class TradeCondition(MappedValue, AmountGeneratorMixin, VariatedMixin):
                       , PropertySheet.Arrow
                       , PropertySheet.TradeCondition
                       , PropertySheet.Order
+                      , PropertySheet.Task # XXX It is probably wrong to have
+                             # Task propertysheet, however many tests fails
+                             # if not present. Cleaning required.
                       )
 
     zope.interface.implements(interfaces.IAmountGenerator,