diff --git a/purchase.py b/purchase.py
index 2295ac5d7c..84dad06eb3 100644
--- a/purchase.py
+++ b/purchase.py
@@ -315,7 +315,7 @@ class PurchaseRequisition(Workflow, ModelSQL, ModelView):
 
     @classmethod
     def view_attributes(cls):
-        return [
+        return super().view_attributes() + [
             ('/tree', 'visual',
                 If(Eval('state') == 'cancelled', 'muted', '')),
             ]