diff --git a/sale_order_route/models/sale_order.py b/sale_order_route/models/sale_order.py
index 30dfd99..d039243 100644
--- a/sale_order_route/models/sale_order.py
+++ b/sale_order_route/models/sale_order.py
@@ -10,13 +10,17 @@ class SaleOrder(models.Model):
 
     route_id = fields.Many2one(
         'stock.location.route', string='Route',
-        ondelete='restrict', readonly=True,
+        ondelete='restrict', readonly=True, track_visibility='onchange',
         states={'draft': [('readonly', False)], 'sent': [('readonly', False)]},
         domain=[('sale_selectable', '=', True)])
 
     def _action_confirm(self):
-        for order in self.filtered(lambda o: o.route_id):
+        # Caution: take into account the scenario where
+        # route_id has a value, then SO is cancelled+back to draft,
+        # then route_id = False and SO is confirmed again
+        for order in self:
+            vals = {'route_id': order.route_id.id or False}
             order.order_line.filtered(
-                lambda l: l.product_id.type in ('product', 'consu')).write(
-                    {'route_id': order.route_id.id})
+                lambda l:
+                l.product_id.type in ('product', 'consu')).write(vals)
         super(SaleOrder, self)._action_confirm()