pos/pos_pricelist/views/point_of_sale_view.xml

<?xml version="1.0"?>
<openerp>
    <data>

        <record id="view_pos_pos_form" model="ir.ui.view">
            <field name="name">pos.order</field>
            <field name="model">pos.order</field>
            <field name="inherit_id" ref="point_of_sale.view_pos_pos_form"/>
            <field name="arch" type="xml">
            	<xpath expr="//field[@name='lines']/tree/field[@name='discount']" position="after">
            		<field name="tax_ids" widget="many2many_tags"/>
            	</xpath>
			</field>
		</record>
		<!-- 
        <record model="ir.ui.view" id="view_pos_pos_form">
            <field name="name">pos.order</field>
            <field name="model">pos.order</field>
            <field name="arch" type="xml">
                <form string="Point of Sale Orders">
                    <header>
                        <button name="%(action_pos_payment)d" string="Payment" class="oe_highlight" type="action" states="draft" context="{'pos_session_id' : session_id}"/>
                        <button name="action_invoice" string="Invoice" type="object" states="paid" attrs="{'readonly': [('partner_id','=',False)]}"/>
                        <button name="refund" string="Return Products" type="object" 
                            attrs="{'invisible':[('state','=','draft')]}"/>
                        <button name="%(action_report_pos_receipt)d" string="Reprint" type="action" states="paid,done,invoiced"/>
                        <field name="state" widget="statusbar" statusbar_visible="draft,paid,done" statusbar_colors='{"cancel":"red"}'/>
                    </header>
                    <sheet>
                    <group col="4" colspan="4">
                        <field name="name"/>
                        <field name="date_order"/>
                        <field name="session_id" required="1"/>
                        <field name="partner_id" on_change="onchange_partner_id(partner_id, context)" domain="[('customer', '=', True)]" context="{'search_default_customer':1}" attrs="{'readonly': [('state','=','invoiced')]}"/>
                    </group>
                    <notebook colspan="4">
                        <page string="Products">
                            <field name="lines" colspan="4" nolabel="1">
                                <tree string="Order lines" editable="bottom">
                                    <field name="product_id" on_change="onchange_product_id(parent.pricelist_id,product_id,qty,parent.partner_id)"/>
                                    <field name="qty" on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                    <field name="price_unit" on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                    <field name="discount"  on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                    <field name="price_subtotal"/>
                                    <field name="price_subtotal_incl"/>
                                </tree>
                                <form string="Order lines">
                                    <group col="4">
                                        <field name="product_id" on_change="onchange_product_id(parent.pricelist_id,product_id,qty,parent.partner_id)"/>
                                        <field name="qty" on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                        <field name="discount"  on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                        <field name="price_unit" on_change="onchange_qty(product_id, discount, qty, price_unit, context)"/>
                                        <field name="price_subtotal" invisible="1"/>
                                        <field name="price_subtotal_incl" invisible="1"/>
                                        <field name="notice"/>
                                    </group>
                                </form>
                            </field>
                            <group class="oe_subtotal_footer oe_right" colspan="2" name="order_total">
                                <field name="amount_tax"/>
                                <div class="oe_subtotal_footer_separator oe_inline">
                                    <label for="amount_total" />
                                    <button name="button_dummy"
                                        states="draft" string="(update)" class="oe_edit_only oe_link"/>
                                </div>
                                <field name="amount_total" nolabel="1" class="oe_subtotal_footer_separator"/>
                            </group>
                            <div class="oe_clear"/>
                        </page>
                        <page string="Payments">
                            <field name="statement_ids" colspan="4" nolabel="1">
                                <tree editable="bottom" string="Statement lines">
                                    <field name="journal_id"/>
                                    <field name="statement_id"/>
                                    <field name="amount"/>
                                </tree>
                            </field>
                        </page>
                        <page string="Extra Info">
                            <group string="General Information">
                                <field name="company_id" groups="base.group_multi_company"/>
                                <field name="location_id" widget="selection" groups="stock.group_locations"/>
                                <field name="user_id" context="{'default_groups_ref': ['base.group_user', 'base.group_partner_manager', 'point_of_sale.group_pos_user']}"/>
                                <field name="pricelist_id" groups="product.group_sale_pricelist" domain="[('type','=','sale')]"/>
                                <field name="picking_id" readonly="1"/>
                                <field name="pos_reference"/>
                            </group>
                            <group string="Accounting Information">
                                <field name="sale_journal" domain="[('type','=','sale')]"/>
                                <field name="invoice_id" readonly="1"
                                    attrs="{'invisible':[('state','&lt;&gt;','invoiced')]}"/>
                                <button name="%(pos_invoice_report)d" string="Re-Print"
                                    icon="gtk-print" type="action" attrs="{'invisible':[('state','&lt;&gt;','invoiced')]}"/>
                                <field name="account_move" readonly="1"
                                    attrs="{'invisible':[('state','&lt;&gt;','done')]}"/>
                            </group>
                        </page>
                        <page string="Notes" >
                            <field name="note"/>
                        </page>
                    </notebook>
                </sheet>
                </form>
            </field>
        </record>
 -->
    </data>
</openerp>