diff --git a/addons/project/project.py b/addons/project/project.py
index 741cae4b91b..df422f4cc8f 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -204,8 +204,8 @@ class project(osv.osv):
     def attachment_tree_view(self, cr, uid, ids, context):
         task_ids = self.pool.get('project.task').search(cr, uid, [('project_id', 'in', ids)])
         domain = [
-            ('|', 
-             '&', 'res_model', '=', 'project.project'), ('res_id', 'in', ids),
+             '|', 
+             '&', ('res_model', '=', 'project.project'), ('res_id', 'in', ids),
              '&', ('res_model', '=', 'project.task'), ('res_id', 'in', task_ids)
 		]
         res_id = ids and ids[0] or False