I'm trying to create a tree view with a button and I'm totally lost. Following some examples I arrived to dessign this view:

<record model="ir.ui.view" id="pricelist_getter_tree">
            <field name="name">pricelist_getter_tree</field>
            <field name="model">bdd.pricelist</field>
            <field name="type">tree</field>
            <field name="arch" type="xml">
                <tree string="Price List">
                    <field name="cus_name"/>
                    <field name="pr_name"/>
                    <field name="pl_amount"/>
                    <field name="pl_speed"/>
                    <field name="pl_hard"/>
                    <field name="pl_setup_price"/>
                    <field name="price_min"/>
                    <field name="pl_profitrate"/>
                    <field name="pl_salescom"/>
                    <field name="pl_price"/>
                    <field name="pl_revenue"/>
                    <button string="Transfer" icon="gtk-redo" name="transfer" type="action"/>
                    <!-- field name="pl_currency"/-->
                </tree>
            </field>
        </record>

But I'm getting an error:

Uncaught TypeError: Cannot read property 'tree_invisible' of undefined

http://localhost:8069/?debug=&db=openerp_db_server&ts=1411455025018#view_type=form&model=bdd.pricelist&menu_id=827&action=1085:18

Any suggestion or guidelines about how to do it? Google isn't helping me much.

Thanks