diff --git a/addons/mail/mail_mail.py b/addons/mail/mail_mail.py
index fa0c18ef529..ebfd19e87b3 100644
--- a/addons/mail/mail_mail.py
+++ b/addons/mail/mail_mail.py
@@ -180,10 +180,7 @@ class mail_mail(osv.Model):
                     references = message.references,
                     object_id=message.res_id and ('%s-%s' % (message.res_id,message.model)),
                     subtype=message.content_subtype,
-                    subtype_alternative=content_subtype_alternative,
-                    # TDE FIXME: what to do with headers ? currently ycommented to avoid bugs
-                    # headers=message.headers and ast.literal_eval(message.headers))
-                    )
+                    subtype_alternative=content_subtype_alternative)
                 res = ir_mail_server.send_email(cr, uid, msg,
                                                 mail_server_id=message.mail_server_id.id,
                                                 context=context)
diff --git a/addons/mail/mail_message.py b/addons/mail/mail_message.py
index 1aa1c34568d..2cd22aa76b4 100644
--- a/addons/mail/mail_message.py
+++ b/addons/mail/mail_message.py
@@ -50,8 +50,7 @@ class mail_message(osv.Model):
     def _shorten_name(self, name):
         if len(name) <= (self._message_record_name_length+3):
             return name
-        else:
-            return name[:18] + '...'
+        return name[:self._message_record_name_length] + '...'
 
     def _get_record_name(self, cr, uid, ids, name, arg, context=None):
         """ Return the related document name, using get_name. """
@@ -318,6 +317,8 @@ class mail_message(osv.Model):
             self.pool.get(model).check_access_rule(cr, uid, mids, mode, context=context)
 
     def create(self, cr, uid, values, context=None):
+        if not values.get('message_id') and values.get('res_id') and values.get('model'):
+            values['message_id'] = tools.generate_tracking_message_id('%(model)s-%(res_id)s'% values)
         newid = super(mail_message, self).create(cr, uid, values, context)
         self.check(cr, uid, [newid], mode='create', context=context)
         self.notify(cr, uid, newid, context=context)
diff --git a/addons/mail/mail_thread.py b/addons/mail/mail_thread.py
index 48d1d87c5ff..eb9b48bbc5f 100644
--- a/addons/mail/mail_thread.py
+++ b/addons/mail/mail_thread.py
@@ -553,9 +553,16 @@ class mail_thread(osv.Model):
             date_server_datetime_str = date_server_datetime.strftime(tools.DEFAULT_SERVER_DATETIME_FORMAT)
             msg_dict['date'] = date_server_datetime_str
 
-        # FP Note: todo - find parent_id
         if 'In-Reply-To' in message:
-            pass
+            parent_ids = self.pool.get('mail.message').search(cr, uid, [('message_id','=',decode(message['In-Reply-To']))])
+            if parent_ids:
+                msg_dict['parent_id'] = parent_ids[0]
+
+        if 'References' in message and 'parent_id' not in msg_dict:
+            parent_ids = self.pool.get('mail.message').search(cr, uid, [('message_id','in',
+                                                                         [x.strip() for x in decode(message['References']).split()])])
+            if parent_ids:
+                msg_dict['parent_id'] = parent_ids[0]
         
         msg_dict['body'], msg_dict['attachments'] = self._message_extract_payload(message)
         return msg_dict
diff --git a/addons/mail/tests/test_mail.py b/addons/mail/tests/test_mail.py
index 01d17c39ebb..e6faf26e0ad 100644
--- a/addons/mail/tests/test_mail.py
+++ b/addons/mail/tests/test_mail.py
@@ -313,7 +313,7 @@ class test_mail(common.TransactionCase):
             for val in read_dict:
                 current = {'_id': val['id']}
                 if val.get('child_ids'):
-                    current['child_ids'] = _flatten(val.get('child_ids'))
+                    current['child_ids'] = _simplify_struct(val.get('child_ids'))
                 res.append(current)
             return res
 
@@ -395,14 +395,12 @@ class test_mail(common.TransactionCase):
             ('read', '=', False)
             ])
         na_count = self.mail_message._needaction_count(cr, uid, domain = [])
-        self.assertTrue(len(notif_ids) == na_count,
+        self.assertEqual(len(notif_ids), na_count,
             'Number of unread notifications (%s) does not match the needaction count (%s)' % (len(notif_ids), na_count))
 
         # Post 4 message on group_pigs
-        msgid1 = group_pigs.message_post(body='My Body')
-        msgid2 = group_pigs.message_post(body='My Body')
-        msgid3 = group_pigs.message_post(body='My Body')
-        msgid4 = group_pigs.message_post(body='My Body')
+        for dummy in range(4):
+            group_pigs.message_post(body='My Body')
 
         # Check there are 4 new needaction on mail.message
         notif_ids = self.mail_notification.search(cr, uid, [
@@ -410,10 +408,39 @@ class test_mail(common.TransactionCase):
             ('read', '=', False)
             ])
         na_count = self.mail_message._needaction_count(cr, uid, domain = [])
-        self.assertTrue(len(notif_ids) == na_count,
+        self.assertEqual(len(notif_ids), na_count,
             'Number of unread notifications after posting messages (%s) does not match the needaction count (%s)' % (len(notif_ids), na_count))
 
         # Check there are 4 needaction on mail.message with particular domain
         na_count = self.mail_message._needaction_count(cr, uid, domain = [('model', '=', 'mail.group'), ('res_id', '=', self.group_pigs_id)])
-        self.assertTrue(na_count == 4,
+        self.assertEqual(na_count, 4,
             'Number of posted message (4) does not match the needaction count with domain mail.group - group pigs (%s)' % (na_count))
+
+    def test_50_thread_parent_resolution(self):
+        """Verify parent/child relationships are correctly established when processing incoming mails"""
+        cr, uid = self.cr, self.uid
+        group_pigs = self.mail_group.browse(cr, uid, self.group_pigs_id)
+        msg1 = group_pigs.message_post(body='My Body', subject='1')
+        msg2 = group_pigs.message_post(body='My Body', subject='2')
+        msg1, msg2 = self.mail_message.browse(cr, uid, [msg1,msg2])
+        self.assertTrue(msg1.message_id, "New message should have a proper message_id")
+
+        # Reply to msg1, make sure the reply is properly attached using the various reply identification mechanisms
+        # 1. In-Reply-To header
+        reply_msg = MAIL_TEMPLATE.format(to='Pretty Pigs <group+pigs@example.com>, other@gmail.com', subject='Re: 1',
+                                         extra='In-Reply-To: %s' % msg1.message_id)
+        self.mail_thread.message_process(cr, uid, None, reply_msg)
+        # 2. References header
+        reply_msg2 = MAIL_TEMPLATE.format(to='Pretty Pigs <group+pigs@example.com>, other@gmail.com', subject='Re: Re: 1',
+                                         extra='References: <2233@a.com>\r\n\t<3edss_dsa@b.com> %s' % msg1.message_id)
+        self.mail_thread.message_process(cr, uid, None, reply_msg2)
+        # 3. Subject contains [<ID>] + model passed to message+process -> only attached to group, not to mail
+        reply_msg3 = MAIL_TEMPLATE.format(to='Pretty Pigs <group+pigs@example.com>, other@gmail.com',
+                                          extra='', subject='Re: [%s] 1' % self.group_pigs_id)
+        self.mail_thread.message_process(cr, uid, 'mail.group', reply_msg3)
+        group_pigs.refresh()
+        msg1.refresh()
+        self.assertEqual(5, len(group_pigs.message_ids), 'group should contain 5 messages')
+        self.assertEqual(2, len(msg1.child_ids), 'msg1 should have 2 children now')
+
+