diff --git a/product/ERP5Form/ListBox.py b/product/ERP5Form/ListBox.py
index 9267e79d0b3c2d7025879d886cd849612c453aee..466a4236e8c410b53bdeee39a22d57159784dcfd 100644
--- a/product/ERP5Form/ListBox.py
+++ b/product/ERP5Form/ListBox.py
@@ -2703,7 +2703,7 @@ class ListBoxValidator(Validator.Validator):
                     error_result_key = '%s_%s' % (my_field.id, o.uid)
                     key = 'field_' + error_result_key
                     try:
-                      value = my_field._validate_helper(key, REQUEST) # We need cell
+                      value = my_field.validator.validate(my_field, key, REQUEST) # We need cell
                       error_result[error_result_key] = value
                       if not result.has_key(o.getUrl()):
                         result[o.getUrl()] = {}