diff --git a/sale.py b/sale.py
index 3c71ffa..da90ae5 100644
--- a/sale.py
+++ b/sale.py
@@ -4,8 +4,6 @@ from trytond.pool import PoolMeta
 from trytond.model import fields
 from trytond.pyson import Eval
 
-__all__ = ['SaleLine']
-
 
 class SaleLine(metaclass=PoolMeta):
     __name__ = 'sale.line'
@@ -22,7 +20,7 @@ class SaleLine(metaclass=PoolMeta):
             },
         depends=['type', 'product', 'product_type'])
 
-    @fields.depends('product')
+    @fields.depends('product', '_parent_product.type')
     def on_change_with_product_type(self, name=None):
         if not self.product:
             return