diff --git a/modules/sale_product_customer/sale.py b/modules/sale_product_customer/sale.py
index b7667aaff9..5d22488fc8 100644
--- a/modules/sale_product_customer/sale.py
+++ b/modules/sale_product_customer/sale.py
@@ -88,6 +88,7 @@ class AmendmentLine(metaclass=PoolMeta):
             ],
         states={
             'invisible': Eval('action') != 'line',
+            'readonly': Eval('state') != 'draft',
             })
 
     @fields.depends('line')