diff --git a/product/ERP5Type/Base.py b/product/ERP5Type/Base.py
index 14ea29e1b83afeb1883e8e0dab3a5a41fb093bc9..cbc51fdec3482de5e2a4b431263ebe3978e491e9 100644
--- a/product/ERP5Type/Base.py
+++ b/product/ERP5Type/Base.py
@@ -855,7 +855,7 @@ class Base( CopyContainer,
     """
     ptype = self.portal_type
     klass = self.__class__
-    aq_key = (ptype, klass) # We do not use _aq_key() here for speed
+    aq_key = self._aq_key()
     initializePortalTypeDynamicProperties(self, klass, ptype, aq_key, \
         self.getPortalObject())
     from Products.ERP5Form.PreferenceTool import createPreferenceToolAccessorList