i want to filter by picking state but when i use this filter it does nothing. any suggestions?


<record id="view_sale_order_search_picking_state" model="ir.ui.view">
    <field name="name">picking state</field>
    <field name="model">sale.order</field>
    <field name="inherit_id" ref="sale.view_sales_order_filter" />
    <field name="arch" type="xml">
        <field name="user_id" position="after">
            <field name="picking_state"/>
        </field>
        <filter name="sales" position="after">
            <filter string="Picking state"  domain="[('picking_state', '=', 'confirmed')]" />
        </filter>
    </field>
</record>