diff --git a/openerp/addons/base/res/res_users.py b/openerp/addons/base/res/res_users.py
index 9a7c780e0b310049512c88e4587af7579d6bb56b..27efb08e3bf52c6c7d11f58de485edd086a7dff6 100644
--- a/openerp/addons/base/res/res_users.py
+++ b/openerp/addons/base/res/res_users.py
@@ -91,7 +91,7 @@ class res_groups(osv.osv):
     _columns = {
         'name': fields.char('Name', required=True, translate=True),
         'users': fields.many2many('res.users', 'res_groups_users_rel', 'gid', 'uid', 'Users'),
-        'model_access': fields.one2many('ir.model.access', 'group_id', 'Access Controls'),
+        'model_access': fields.one2many('ir.model.access', 'group_id', 'Access Controls', copy=True),
         'rule_groups': fields.many2many('ir.rule', 'rule_group_rel',
             'group_id', 'rule_group_id', 'Rules', domain=[('global', '=', False)]),
         'menu_access': fields.many2many('ir.ui.menu', 'ir_ui_menu_group_rel', 'gid', 'menu_id', 'Access Menu'),