Open Order Lines can be without start and stop dates.

master/bt5/vifib_erp5/PropertySheetTemplateItem/portal_property_sheets/VifibOpenSaleOrderLineConstraint/property_set_constraint.xml

@@ -22,8 +22,6 @@
             <key> <string>constraint_property</string> </key>
             <value>
               <tuple>
-                <string>start_date</string>
-                <string>stop_date</string>
                 <string>quantity</string>
                 <string>price</string>
               </tuple>

master/bt5/vifib_erp5/bt/revision

-403
\ No newline at end of file
+404
\ No newline at end of file