diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 110012bbc07..ef13253864b 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -1524,6 +1524,8 @@ class BaseModel(object):
         error_msgs = []
         for constraint in self._constraints:
             fun, msg, fields = constraint
+            # We don't pass around the context here: validation code
+            # must always yield the same results.
             if not fun(self, cr, uid, ids):
                 # Check presence of __call__ directly instead of using
                 # callable() because it will be deprecated as of Python 3.0