diff --git a/product/ERP5Type/FormulatorPatch.py b/product/ERP5Type/FormulatorPatch.py
index 290ead26a7827cd0edada5efe5eb75f2897815a0..dd459f95095f1252b46bf87e639283793961c137 100755
--- a/product/ERP5Type/FormulatorPatch.py
+++ b/product/ERP5Type/FormulatorPatch.py
@@ -62,6 +62,7 @@ Field.generate_field_key = PatchedField.generate_field_key
 Field.render = PatchedField.render
 
 from Products.Formulator.Validator import SelectionValidator
+from Products.Formulator.Validator import StringBaseValidator
 
 def SelectionValidator_validate(self, field, key, REQUEST):
     value = StringBaseValidator.validate(self, field, key, REQUEST)