diff --git a/category.py b/category.py
index 6fd2858296..78587f8de4 100644
--- a/category.py
+++ b/category.py
@@ -5,7 +5,6 @@ class Category(OSV):
     "Product Category"
     _name = "product.category"
     _description = __doc__
-    _order = "parent,name"
 
     name = fields.Char('Name', size=64, required=True)
     complete_name = fields.Function('get_complete_name', type="char", string='Complete Name')
@@ -13,6 +12,11 @@ class Category(OSV):
     childs = fields.One2Many('product.category', 'parent',
             string='Childs')
 
+    def __init__(self):
+        super(Category, self).__init__()
+        self._order.insert(0, ('parent', 'ASC'))
+        self._order.insert(1, ('name', 'ASC'))
+
     def get_complete_name(self, cursor, user, ids, name, arg, context):
         res = self.name_get(cursor, user, ids, context)
         return dict(res)
diff --git a/uom.py b/uom.py
index 4813674d35..6bff95303d 100644
--- a/uom.py
+++ b/uom.py
@@ -8,10 +8,13 @@ class UomCategory(OSV):
     'Product uom category'
     _name = 'product.uom.category'
     _description = __doc__
-    _order = 'name'
     name = fields.Char('Name', size=64, required=True)
     uoms = fields.One2Many('product.uom', 'category', 'Unit of Measures')
 
+    def __init__(self):
+        super(UomCategory, self).__init__()
+        self._order.insert(0, ('name', 'ASC'))
+
 UomCategory()
 
 
@@ -19,7 +22,6 @@ class Uom(OSV):
     'Unit of measure'
     _name = 'product.uom'
     _description = __doc__
-    _order = 'name'
     name = fields.Char('Name', size=64, required=True, states=STATES,)
     symbol = fields.Char('Symbol', size=10, required=True, states=STATES,)
     category = fields.Many2One('product.uom.category', 'UOM Category',
@@ -37,6 +39,10 @@ class Uom(OSV):
                               required=True, states=STATES,)
     active = fields.Boolean('Active')
 
+    def __init__(self):
+        super(Uom, self).__init__()
+        self._order.insert(0, ('name', 'ASC'))
+
     def default_rate(self, cursor, user, context=None):
         return 1.0