diff -r c9861a9a8606 -r c7442401b446 ztfy/utils/timezone/utility.py
--- a/ztfy/utils/timezone/utility.py	Wed Sep 08 07:45:41 2010 +0200
+++ b/ztfy/utils/timezone/utility.py	Wed Sep 08 07:46:09 2010 +0200
@@ -24,6 +24,7 @@
 from interfaces import IServerTimezone
 
 # import Zope3 packages
+from zope.app.container.contained import Contained
 from zope.interface import implements
 from zope.schema.fieldproperty import FieldProperty
 
@@ -32,7 +33,7 @@
 from ztfy.utils import _
 
 
-class ServerTimezoneUtility(Persistent):
+class ServerTimezoneUtility(Persistent, Contained):
 
     implements(IServerTimezone)