--- a/src/pyams_utils/zmi/timezone.py	Tue Apr 10 14:44:20 2018 +0200
+++ b/src/pyams_utils/zmi/timezone.py	Tue Apr 10 14:45:34 2018 +0200
@@ -35,6 +35,8 @@
 class ServerTimezonePropertiesEditForm(AdminDialogEditForm):
     """Server timezone properties edit form"""
 
+    prefix = 'timezone_properties.'
+
     legend = _("Update server timezone properties")
     fields = field.Fields(IServerTimezone)
     ajax_handler = 'properties.json'