Hello, I have Odoo 8.

In the tree view of Warehouse -> All the operations -> Delivery orders, when I click on the search button I see the option to group by several criterias: state, order date, etc.

I want to add a new field to group by, how can I do this? (question 1) Also I try to add a field to search on, but not works (the search criteria not appears). My code is:

<record model="ir.ui.view" id="stock_picking_filter_search">
            <field name="name">stock.picking.tree.filter_search</field>
            <field name="model">stock.picking</field>
            <field name="arch" type="xml">
                <search>
                    <field name="metodo_de_entrega" string="Método de entrega" />
                </search>
            </field>
        </record>

What is my mistake? (question 2) Thanks!