diff -r a0ccc84aaa24 location.py
--- a/trytond/trytond/modules/stock/location.py	Mon Oct 20 15:08:22 2014 +0200
+++ b/trytond/trytond/modules/stock/location.py	Mon Nov 03 13:36:23 2014 +0100
@@ -161,6 +161,11 @@
         return [(cls._rec_name,) + tuple(clause[1:])]

     @classmethod
+    def _quantity_grouping_and_key(cls):
+        product_id = Transaction().context['product']
+        return ('product', ), (product_id,)
+
+    @classmethod
     def get_quantity(cls, locations, name):
         pool = Pool()
         Product = pool.get('product.product')
@@ -192,12 +197,13 @@
         pbl = {}
         for sub_locations in grouped_slice(locations):
             location_ids = [l.id for l in sub_locations]
+            grouping, key = cls._quantity_grouping_and_key()
             with Transaction().set_context(context):
                 pbl.update(Product.products_by_location(
                         location_ids=location_ids, product_ids=[product_id],
-                        with_childs=True))
+                        with_childs=True, grouping=grouping))

-        return dict((loc.id, pbl.get((loc.id, product_id), 0))
+        return dict((loc.id, pbl.get((loc.id,) + key, 0))
             for loc in locations)

     @classmethod