diff --git a/addons/account/models/account.py b/addons/account/models/account.py
index 09923efec07..48ef95bc276 100644
--- a/addons/account/models/account.py
+++ b/addons/account/models/account.py
@@ -149,7 +149,7 @@ class AccountAccount(models.Model):
     @api.one
     def copy(self, default=None):
         default = dict(default or {})
-        default.update(code=_("%s (copy)") % (self.code or ''))
+        default.setdefault('code', _("%s (copy)") % (self.code or ''))
         return super(AccountAccount, self).copy(default)
 
     @api.multi
diff --git a/addons/account/models/account_payment.py b/addons/account/models/account_payment.py
index 1bf47b0f41d..4c7ba8eaeea 100644
--- a/addons/account/models/account_payment.py
+++ b/addons/account/models/account_payment.py
@@ -384,7 +384,15 @@ class account_payment(models.Model):
         #Reconcile with the invoices
         if self.payment_difference_handling == 'reconcile' and self.payment_difference:
             writeoff_line = self._get_shared_move_line_vals(0, 0, 0, move.id, False)
-            debit_wo, credit_wo, amount_currency_wo, currency_id = aml_obj.with_context(date=self.payment_date).compute_amount_fields(self.payment_difference, self.currency_id, self.company_id.currency_id, invoice_currency)
+            amount_currency_wo, currency_id = aml_obj.with_context(date=self.payment_date).compute_amount_fields(self.payment_difference, self.currency_id, self.company_id.currency_id, invoice_currency)[2:]
+            # the writeoff debit and credit must be computed from the invoice residual in company currency
+            # minus the payment amount in company currency, and not from the payment difference in the payment currency
+            # to avoid loss of precision during the currency rate computations. See revision 20935462a0cabeb45480ce70114ff2f4e91eaf79 for a detailed example.
+            total_residual_company_signed = sum(invoice.residual_company_signed for invoice in self.invoice_ids)
+            total_payment_company_signed = self.currency_id.with_context(date=self.payment_date).compute(self.amount, self.company_id.currency_id)
+            amount_wo = total_residual_company_signed - total_payment_company_signed
+            debit_wo = amount_wo > 0 and amount_wo or 0.0
+            credit_wo = amount_wo < 0 and -amount_wo or 0.0
             writeoff_line['name'] = _('Counterpart')
             writeoff_line['account_id'] = self.writeoff_account_id.id
             writeoff_line['debit'] = debit_wo
diff --git a/addons/account_analytic_default/models/account_analytic_default.py b/addons/account_analytic_default/models/account_analytic_default.py
index 85ec2199f0f..9ef2add29bc 100644
--- a/addons/account_analytic_default/models/account_analytic_default.py
+++ b/addons/account_analytic_default/models/account_analytic_default.py
@@ -65,7 +65,10 @@ class AccountInvoiceLine(models.Model):
         return res
 
     def _set_additional_fields(self, invoice):
-        rec = self.env['account.analytic.default'].account_get(self.product_id.id, self.invoice_id.partner_id.id, self.env.uid,
-                                                               fields.Date.today(), company_id=self.company_id.id)
-        self.account_analytic_id = rec.analytic_id.id
+        if not self.account_analytic_id:
+            rec = self.env['account.analytic.default'].account_get(
+                self.product_id.id, self.invoice_id.partner_id.id, self.env.uid,
+                fields.Date.today(), company_id=self.company_id.id)
+            if rec:
+                self.account_analytic_id = rec.analytic_id.id
         super(AccountInvoiceLine, self)._set_additional_fields(invoice)
diff --git a/addons/event/views/event_views.xml b/addons/event/views/event_views.xml
index 886bec31019..12bd833ec65 100644
--- a/addons/event/views/event_views.xml
+++ b/addons/event/views/event_views.xml
@@ -244,7 +244,7 @@
                     <filter string="Unread Messages" name="message_needaction" domain="[('message_needaction','=',True)]"/>
                     <separator/>
                     <filter string="Unconfirmed" name="draft" domain="[('state','=','draft')]" help="Events in New state"/>
-                    <filter string="Confirmed" domain="[('state','=','confirm')]" help="Confirmed events"/>
+                    <filter name="confirm" string="Confirmed" domain="[('state','=','confirm')]" help="Confirmed events"/>
                     <separator/>
                     <filter string="My Events" help="My Events" domain="[('user_id','=',uid)]"/>
                     <separator/>
diff --git a/addons/mail/wizard/mail_compose_message.py b/addons/mail/wizard/mail_compose_message.py
index 176ea88aec1..f55854a704e 100644
--- a/addons/mail/wizard/mail_compose_message.py
+++ b/addons/mail/wizard/mail_compose_message.py
@@ -12,18 +12,17 @@ from openerp.tools.safe_eval import safe_eval as eval
 EXPRESSION_PATTERN = re.compile('(\$\{.+?\})')
 
 
-def _reopen(self, res_id, model):
+def _reopen(self, res_id, model, context=None):
+    # save original model in context, because selecting the list of available
+    # templates requires a model in context
+    context = dict(context or {}, default_model=model)
     return {'type': 'ir.actions.act_window',
             'view_mode': 'form',
             'view_type': 'form',
             'res_id': res_id,
             'res_model': self._name,
             'target': 'new',
-            # save original model in context, because selecting the list of available
-            # templates requires a model in context
-            'context': {
-                'default_model': model,
-            },
+            'context': context,
             }
 
 
@@ -409,7 +408,7 @@ class MailComposer(models.TransientModel):
             # generate the saved template
             record.write({'template_id': template.id})
             record.onchange_template_id_wrapper()
-            return _reopen(self, record.id, record.model)
+            return _reopen(self, record.id, record.model, context=self._context)
 
     #------------------------------------------------------
     # Template rendering
diff --git a/addons/payment_transfer/i18n/payment_transfer.pot b/addons/payment_transfer/i18n/payment_transfer.pot
index 8d148467a56..13e0d0166f8 100644
--- a/addons/payment_transfer/i18n/payment_transfer.pot
+++ b/addons/payment_transfer/i18n/payment_transfer.pot
@@ -6,8 +6,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Odoo Server 9.saas~10c\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2016-08-18 14:07+0000\n"
-"PO-Revision-Date: 2016-08-18 14:07+0000\n"
+"POT-Creation-Date: 2016-12-14 14:52+0000\n"
+"PO-Revision-Date: 2016-12-14 14:52+0000\n"
 "Last-Translator: <>\n"
 "Language-Team: \n"
 "MIME-Version: 1.0\n"
@@ -15,6 +15,18 @@ msgstr ""
 "Content-Transfer-Encoding: \n"
 "Plural-Forms: \n"
 
+#. module: payment_transfer
+#: code:addons/payment_transfer/models/payment_acquirer.py:32
+#, python-format
+msgid "<div>\n"
+"<h3>Please use the following transfer details</h3>\n"
+"<h4>%(bank_title)s</h4>\n"
+"%(bank_accounts)s\n"
+"<h4>Communication</h4>\n"
+"<p>Please use the order name as communication reference.</p>\n"
+"</div>"
+msgstr ""
+
 #. module: payment_transfer
 #: code:addons/payment_transfer/models/payment_acquirer.py:68
 #, python-format
diff --git a/addons/payment_transfer/models/payment_acquirer.py b/addons/payment_transfer/models/payment_acquirer.py
index a8d47098c6c..8b6ba44f202 100644
--- a/addons/payment_transfer/models/payment_acquirer.py
+++ b/addons/payment_transfer/models/payment_acquirer.py
@@ -29,13 +29,13 @@ class TransferPaymentAcquirer(osv.Model):
         accounts = self.pool['account.journal'].browse(cr, uid, journal_ids, context=context).mapped('bank_account_id').name_get()
         bank_title = _('Bank Accounts') if len(accounts) > 1 else _('Bank Account')
         bank_accounts = ''.join(['<ul>'] + ['<li>%s</li>' % name for id, name in accounts] + ['</ul>'])
-        post_msg = '''<div>
+        post_msg = _('''<div>
 <h3>Please use the following transfer details</h3>
 <h4>%(bank_title)s</h4>
 %(bank_accounts)s
 <h4>Communication</h4>
 <p>Please use the order name as communication reference.</p>
-</div>''' % {
+</div>''') % {
             'bank_title': bank_title,
             'bank_accounts': bank_accounts,
         }
diff --git a/addons/point_of_sale/models/pos_order.py b/addons/point_of_sale/models/pos_order.py
index d9891283fc9..77a3c91ec7c 100644
--- a/addons/point_of_sale/models/pos_order.py
+++ b/addons/point_of_sale/models/pos_order.py
@@ -52,36 +52,29 @@ class PosOrder(models.Model):
         }
 
     # This deals with orders that belong to a closed session. In order
-    # to recover from this we:
-    # - assign the order to another compatible open session
-    # - if that doesn't exist, create a new one
+    # to recover from this situation we create a new rescue session,
+    # making it obvious that something went wrong.
+    # A new, separate, rescue session is preferred for every such recovery,
+    # to avoid adding unrelated orders to live sessions.
     def _get_valid_session(self, order):
         PosSession = self.env['pos.session']
         closed_session = PosSession.browse(order['pos_session_id'])
-        open_session = PosSession.search(
-            [('state', '=', 'opened'),
-             ('config_id', '=', closed_session.config_id.id),
-             ('user_id', '=', closed_session.user_id.id)],
-            limit=1, order="start_at DESC")
 
         _logger.warning('session %s (ID: %s) was closed but received order %s (total: %s) belonging to it',
                         closed_session.name,
                         closed_session.id,
                         order['name'],
                         order['amount_total'])
+        _logger.warning('attempting to create recovery session for saving order %s', order['name'])
+        new_session = PosSession.create({
+            'config_id': closed_session.config_id.id,
+            'name': _('(RESCUE FOR %(session)s)') % {'session': closed_session.name},
+            'rescue': True,    # avoid conflict with live sessions
+        })
+        # bypass opening_control (necessary when using cash control)
+        new_session.signal_workflow('open')
 
-        if open_session:
-            _logger.warning('using session %s (ID: %s) for order %s instead',
-                            open_session.name,
-                            open_session.id,
-                            order['name'])
-            return open_session
-        else:
-            _logger.warning('attempting to create new session for order %s', order['name'])
-            new_session = PosSession.create({'config_id': closed_session.config_id.id})
-            # bypass opening_control (necessary when using cash control)
-            new_session.signal_workflow('open')
-            return new_session
+        return new_session
 
     def _match_payment_to_invoice(self, order):
         account_precision = self.env['decimal.precision'].precision_get('Account')
@@ -415,7 +408,7 @@ class PosOrder(models.Model):
             # set name based on the sequence specified on the config
             session = self.env['pos.session'].browse(values['session_id'])
             values['name'] = session.config_id.sequence_id._next()
-            values.setdefault('session_id', session.config_id.pricelist_id.id)
+            values.setdefault('pricelist_id', session.config_id.pricelist_id.id)
         else:
             # fallback on any pos.order sequence
             values['name'] = self.env['ir.sequence'].next_by_code('pos.order')
diff --git a/addons/point_of_sale/models/pos_session.py b/addons/point_of_sale/models/pos_session.py
index 01576578fed..966743da560 100644
--- a/addons/point_of_sale/models/pos_session.py
+++ b/addons/point_of_sale/models/pos_session.py
@@ -160,8 +160,12 @@ class PosSession(models.Model):
 
             statements.append(ABS.with_context(ctx).sudo(uid).create(st_values).id)
 
+        unique_name = self.env['ir.sequence'].with_context(ctx).next_by_code('pos.session')
+        if values.get('name'):
+            unique_name += ' ' + values['name']
+
         values.update({
-            'name': self.env['ir.sequence'].with_context(ctx).next_by_code('pos.session'),
+            'name': unique_name,
             'statement_ids': [(6, 0, statements)],
             'config_id': config_id
         })
@@ -236,3 +240,32 @@ class PosSession(models.Model):
             'target': 'self',
             'url':   '/pos/web/',
         }
+
+    @api.multi
+    def open_cashbox(self):
+        self.ensure_one()
+        context = dict(self._context)
+        balance_type = context.get('balance') or 'start'
+        context['bank_statement_id'] = self.cash_register_id.id
+        context['balance'] = balance_type
+
+        action = {
+            'name': _('Cash Control'),
+            'view_type': 'form',
+            'view_mode': 'form',
+            'res_model': 'account.bank.statement.cashbox',
+            'view_id': self.env.ref('account.view_account_bnk_stmt_cashbox').id,
+            'type': 'ir.actions.act_window',
+            'context': context,
+            'target': 'new'
+        }
+
+        cashbox_id = None
+        if balance_type == 'start':
+            cashbox_id = self.cash_register_id.cashbox_start_id.id
+        else:
+            cashbox_id = self.cash_register_id.cashbox_end_id.id
+        if cashbox_id:
+            action['res_id'] = cashbox_id
+
+        return action
diff --git a/addons/point_of_sale/static/src/js/gui.js b/addons/point_of_sale/static/src/js/gui.js
index 365a27b1cc6..0fca3607f81 100644
--- a/addons/point_of_sale/static/src/js/gui.js
+++ b/addons/point_of_sale/static/src/js/gui.js
@@ -114,7 +114,7 @@ var Gui = core.Class.extend({
                 this.current_screen.hide();
             }
             this.current_screen = screen;
-            this.current_screen.show();
+            this.current_screen.show(refresh);
         }
     },
     
diff --git a/addons/point_of_sale/static/src/js/models.js b/addons/point_of_sale/static/src/js/models.js
index 904cfcb9c42..d0cb2adba9f 100644
--- a/addons/point_of_sale/static/src/js/models.js
+++ b/addons/point_of_sale/static/src/js/models.js
@@ -1074,7 +1074,8 @@ exports.Orderline = Backbone.Model.extend({
     init_from_JSON: function(json) {
         this.product = this.pos.db.get_product_by_id(json.product_id);
         if (!this.product) {
-            console.error('ERROR: attempting to recover product not available in the point of sale');
+            console.error('ERROR: attempting to recover product ID', json.product_id,
+                'not available in the point of sale. Correct the product or clean the browser cache.');
         }
         this.price = json.price_unit;
         this.set_discount(json.discount);
diff --git a/addons/point_of_sale/static/src/js/screens.js b/addons/point_of_sale/static/src/js/screens.js
index 35d57a020d9..5bfa8f1e309 100644
--- a/addons/point_of_sale/static/src/js/screens.js
+++ b/addons/point_of_sale/static/src/js/screens.js
@@ -272,8 +272,9 @@ var ScaleScreenWidget = ScreenWidget.extend({
         });
 
         this.$('.next,.buy-product').click(function(){
-            self.order_product();
             self.gui.show_screen(self.next_screen);
+            // add product *after* switching screen to scroll properly
+            self.order_product();
         });
 
         queue.schedule(function(){
@@ -937,10 +938,12 @@ var ProductScreenWidget = ScreenWidget.extend({
        }
     },
 
-    show: function(){
+    show: function(reset){
         this._super();
-        this.product_categories_widget.reset_category();
-        this.numpad.state.reset();
+        if (reset) {
+            this.product_categories_widget.reset_category();
+            this.numpad.state.reset();
+        }
     },
 
     close: function(){
diff --git a/addons/point_of_sale/views/pos_session_view.xml b/addons/point_of_sale/views/pos_session_view.xml
index 4cf44bbf1f3..d6fb4cc6953 100644
--- a/addons/point_of_sale/views/pos_session_view.xml
+++ b/addons/point_of_sale/views/pos_session_view.xml
@@ -48,18 +48,18 @@
                                 <span class="o_stat_text">Money Out</span>
                             </div>
                         </button>
-                        <button name="%(account.action_view_account_bnk_stmt_cashbox)d"
+                        <button name="open_cashbox"
                             class="oe_stat_button"
                             attrs="{'invisible':['|', ('cash_control', '=', False), ('state', '!=', 'opening_control')]}"
                             icon="fa-money"
-                            type="action" context="{'balance': 'start', 'bank_statement_id': cash_register_id}">
+                            type="object" context="{'balance': 'start'}">
                             <span class="o_stat_text">Set Opening Balance</span>
                         </button>
-                        <button name="%(account.action_view_account_bnk_stmt_cashbox)d"
+                        <button name="open_cashbox"
                             class="oe_stat_button"
                             attrs="{'invisible':['|', '|', ('cash_control', '=', False), ('state', '=', 'opening_control'), ('state', '=', 'closed')]}"
                             icon="fa-money"
-                            type="action" context="{'balance': 'end', 'bank_statement_id': cash_register_id}">
+                            type="object" context="{'balance': 'end'}">
                             <span class="o_stat_text">Set Closing Balance</span>
                         </button>
                     </div>
diff --git a/addons/report/models/report.py b/addons/report/models/report.py
index 52a1a1f4a38..f3508872202 100644
--- a/addons/report/models/report.py
+++ b/addons/report/models/report.py
@@ -200,7 +200,7 @@ class Report(osv.Model):
         # Get the ir.actions.report.xml record we are working on.
         report = self._get_report_from_name(cr, uid, report_name)
         # Check if we have to save the report or if we have to get one from the db.
-        save_in_attachment = self._check_attachment_use(cr, uid, ids, report)
+        save_in_attachment = self._check_attachment_use(cr, uid, ids, report, context=context)
         # Get the paperformat associated to the report, otherwise fallback on the company one.
         if not report.paperformat_id:
             user = self.pool['res.users'].browse(cr, uid, uid)
@@ -273,7 +273,8 @@ class Report(osv.Model):
         return self._run_wkhtmltopdf(
             cr, uid, headerhtml, footerhtml, contenthtml, context.get('landscape'),
             paperformat, specific_paperformat_args, save_in_attachment,
-            context.get('set_viewport_size')
+            context.get('set_viewport_size'),
+            context
         )
 
     @api.v8
@@ -319,7 +320,7 @@ class Report(osv.Model):
     # Report generation helpers
     #--------------------------------------------------------------------------
     @api.v7
-    def _check_attachment_use(self, cr, uid, ids, report):
+    def _check_attachment_use(self, cr, uid, ids, report, context=None):
         """ Check attachment_use field. If set to true and an existing pdf is already saved, load
         this one now. Else, mark save it.
         """
@@ -328,7 +329,7 @@ class Report(osv.Model):
         save_in_attachment['loaded_documents'] = {}
 
         if report.attachment:
-            records = self.pool[report.model].browse(cr, uid, ids)
+            records = self.pool[report.model].browse(cr, uid, ids, context=context)
             filenames = self._attachment_filename(cr, uid, records, report)
             attachments = None
             if report.attachment_use:
@@ -380,7 +381,7 @@ class Report(osv.Model):
     def _check_wkhtmltopdf(self):
         return wkhtmltopdf_state
 
-    def _run_wkhtmltopdf(self, cr, uid, headers, footers, bodies, landscape, paperformat, spec_paperformat_args=None, save_in_attachment=None, set_viewport_size=False):
+    def _run_wkhtmltopdf(self, cr, uid, headers, footers, bodies, landscape, paperformat, spec_paperformat_args=None, save_in_attachment=None, set_viewport_size=False, context=None):
         """Execute wkhtmltopdf as a subprocess in order to convert html given in input into a pdf
         document.
 
@@ -483,7 +484,7 @@ class Report(osv.Model):
                             'res_id': reporthtml[0],
                         }
                         try:
-                            self.pool['ir.attachment'].create(cr, uid, attachment)
+                            self.pool['ir.attachment'].create(cr, uid, attachment, context)
                         except AccessError:
                             _logger.info("Cannot save PDF report %r as attachment", attachment['name'])
                         else:
diff --git a/addons/web/static/src/js/views/form_widgets.js b/addons/web/static/src/js/views/form_widgets.js
index 3b4628322f7..616e3e1aa07 100644
--- a/addons/web/static/src/js/views/form_widgets.js
+++ b/addons/web/static/src/js/views/form_widgets.js
@@ -1014,6 +1014,7 @@ var FieldReference = common.AbstractField.extend(common.ReinitializeFieldMixin,
         this.m2o = new FieldMany2One(this.fm, { attrs: {
             name: 'Referenced Document',
             modifiers: JSON.stringify({readonly: this.get('effective_readonly')}),
+            context: this.build_context().eval(),
         }});
         this.m2o.on("change:value", this, this.data_changed);
         this.m2o.appendTo(this.$el);
diff --git a/doc/cla/individual/hhgabelgaard.md b/doc/cla/individual/hhgabelgaard.md
new file mode 100644
index 00000000000..e873ef3f5e4
--- /dev/null
+++ b/doc/cla/individual/hhgabelgaard.md
@@ -0,0 +1,11 @@
+Denmark, 2016-05-06
+
+I hereby agree to the terms of the Odoo Individual Contributor License
+Agreement v1.0.
+
+I declare that I am authorized and able to make this agreement and sign this
+declaration.
+
+Signed,
+
+Hans Henrik Gabelgaard hhg@gabelgaard.org https://github.com/hhgabelgaard
\ No newline at end of file
diff --git a/openerp/models.py b/openerp/models.py
index e73e1827217..2aac55edefe 100644
--- a/openerp/models.py
+++ b/openerp/models.py
@@ -845,10 +845,11 @@ class BaseModel(object):
         methods = []
         for attr, func in getmembers(cls, is_constraint):
             for name in func._constrains:
-                if name not in cls._fields:
+                field = cls._fields.get(name)
+                if not field:
                     _logger.warning("method %s.%s: @constrains parameter %r is not a field name", cls._name, attr, name)
-                if not cls._fields[name].store:
-                    _logger.warning("method %s.%s: @constrains parameter %r is not stored", cls._name, attr, name)
+                if not (field.store or field.column and field.column._fnct_inv):
+                    _logger.warning("method %s.%s: @constrains parameter %r is not writeable", cls._name, attr, name)
             methods.append(func)
 
         # optimization: memoize result on cls, it will not be recomputed