I have and act_window which will open by default my custom filter (group_by):

<record id="master_equipment_act_window" model="ir.actions.act_window">
        <field name="name">Equipment</field>        
        <field name="type">ir.actions.act_window</field>
        <field name="res_model">model.name</field>
        <field name="view_mode">tree,form,kanban</field>
        <field name="context">{'search_default_group_location':1}</field>
        <field name="search_view_id" ref="my_search_view"/> 
        <field name="help" type="html">
            <p class="oe_view_nocontent_create">                Empty list.            </p>            
            <p>Please create one.</p>
        </field>
    </record>

 The search:
 <filter name="group_location" string="Location" context="{'group_by':'location'}"/>

By default, odoo will group the result in tree view by location, but needs to click > the arrow button to open 
and view the results. Is it possible to open by default the result without clicking the arrow button? Thanks.