diff --git a/opportunity.py b/opportunity.py
index f815ad96ee..99895ce800 100644
--- a/opportunity.py
+++ b/opportunity.py
@@ -290,8 +290,8 @@ class SaleOpportunityLine(ModelSQL, ModelView):
         on_change_with=['unit']), 'get_unit_digits')
     sale_line = fields.Many2One('sale.line', 'Sale Line', readonly=True,
             states={
-                'invisible': Not(Equal(Eval('_parent_opportunity.state'),
-                    'converted')),
+                'invisible': Not(Equal(Get(Eval('_parent_opportunity', {}),
+                        'state'), 'converted')),
             })
 
     def __init__(self):