diff --git a/address.py b/address.py
index a1b6c0b6c6..d109db75e6 100644
--- a/address.py
+++ b/address.py
@@ -4,7 +4,7 @@
 from trytond.model import ModelView, ModelSQL, fields
 from trytond.pyson import Eval, If
 from trytond.transaction import Transaction
-from trytond.backend import TableHandler
+from trytond import backend
 
 __all__ = ['Address']
 
@@ -33,9 +33,7 @@ class Address(ModelSQL, ModelView):
             'Subdivision', domain=[('country', '=', Eval('country'))],
             states=STATES, depends=['active', 'country'])
     active = fields.Boolean('Active')
-    sequence = fields.Integer("Sequence",
-        order_field='(%(table)s.sequence IS NULL) %(order)s, '
-        '%(table)s.sequence %(order)s')
+    sequence = fields.Integer("Sequence")
     full_address = fields.Function(fields.Text('Full Address'),
             'get_full_address')
 
@@ -50,6 +48,7 @@ class Address(ModelSQL, ModelView):
 
     @classmethod
     def __register__(cls, module_name):
+        TableHandler = backend.get('TableHandler')
         cursor = Transaction().cursor
         table = TableHandler(cursor, cls, module_name)
 
@@ -58,6 +57,11 @@ class Address(ModelSQL, ModelView):
         # Migration from 2.4: drop required on sequence
         table.not_null_action('sequence', action='remove')
 
+    @staticmethod
+    def order_sequence(tables):
+        table, _ = tables[None]
+        return [table.sequence == None, table.sequence]
+
     @staticmethod
     def default_active():
         return True
diff --git a/category.xml b/category.xml
index 20c84b3889..d1b88ed03e 100644
--- a/category.xml
+++ b/category.xml
@@ -23,7 +23,7 @@ this repository contains the full copyright notices and license terms. -->
         <record model="ir.action.act_window" id="act_category_tree">
             <field name="name">Categories</field>
             <field name="res_model">party.category</field>
-            <field name="domain">[('parent', '=', False)]</field>
+            <field name="domain">[('parent', '=', None)]</field>
         </record>
         <record model="ir.action.act_window.view" id="act_category_tree_view1">
             <field name="sequence" eval="10"/>
diff --git a/contact_mechanism.py b/contact_mechanism.py
index ed2f981c94..9c979abd9e 100644
--- a/contact_mechanism.py
+++ b/contact_mechanism.py
@@ -3,7 +3,7 @@
 from trytond.model import ModelView, ModelSQL, fields
 from trytond.pyson import Eval
 from trytond.transaction import Transaction
-from trytond.backend import TableHandler
+from trytond import backend
 
 __all__ = ['ContactMechanism']
 
@@ -39,9 +39,7 @@ class ContactMechanism(ModelSQL, ModelView):
     party = fields.Many2One('party.party', 'Party', required=True,
         ondelete='CASCADE', states=STATES, select=True, depends=DEPENDS)
     active = fields.Boolean('Active', select=True)
-    sequence = fields.Integer('Sequence',
-        order_field='(%(table)s.sequence IS NULL) %(order)s, '
-        '%(table)s.sequence %(order)s')
+    sequence = fields.Integer('Sequence')
     email = fields.Function(fields.Char('E-Mail', states={
         'invisible': Eval('type') != 'email',
         'required': Eval('type') == 'email',
@@ -92,6 +90,7 @@ class ContactMechanism(ModelSQL, ModelView):
 
     @classmethod
     def __register__(cls, module_name):
+        TableHandler = backend.get('TableHandler')
         cursor = Transaction().cursor
         table = TableHandler(cursor, cls, module_name)
 
@@ -100,6 +99,11 @@ class ContactMechanism(ModelSQL, ModelView):
         # Migration from 2.4: drop required on sequence
         table.not_null_action('sequence', action='remove')
 
+    @staticmethod
+    def order_sequence(tables):
+        table, _ = tables[None]
+        return [table.sequence == None, table.sequence]
+
     @staticmethod
     def default_type():
         return 'phone'
diff --git a/party.py b/party.py
index ca97021571..ce0dd9c007 100644
--- a/party.py
+++ b/party.py
@@ -34,8 +34,6 @@ class Party(ModelSQL, ModelView):
     name = fields.Char('Name', required=True, select=True,
         states=STATES, depends=DEPENDS)
     code = fields.Char('Code', required=True, select=True,
-        order_field=("%(table)s.code_length %(order)s, "
-            "%(table)s.code %(order)s"),
         states={
             'readonly': Eval('code_readonly', True),
             },
@@ -85,6 +83,11 @@ class Party(ModelSQL, ModelView):
                 })
         cls._order.insert(0, ('name', 'ASC'))
 
+    @staticmethod
+    def order_code(tables):
+        table, _ = tables[None]
+        return [table.code_length, table.code]
+
     @staticmethod
     def default_active():
         return True