diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index a981f21f674..f0c71c1199f 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -320,6 +320,8 @@ class stock_picking(osv.osv):
     _description = "Packing list"
     def _set_maximum_date(self, cr, uid, ids, name, value, arg, context):
         if not value: return False
+        if isinstance(ids, (int, long)):
+            ids=[ids]
         for pick in self.browse(cr, uid, ids, context):
             cr.execute("""update stock_move set
                     date_planned=%s 
@@ -330,6 +332,8 @@ class stock_picking(osv.osv):
 
     def _set_minimum_date(self, cr, uid, ids, name, value, arg, context):
         if not value: return False
+        if isinstance(ids, (int, long)):
+            ids=[ids]
         for pick in self.browse(cr, uid, ids, context):
             cr.execute("""update stock_move set
                     date_planned=%s