I have many filter in place, created trough some xml migrated from V8 but on Odoo10 are not applied.

Example:

<record id= "Pos_orders_filter_view" model= "ir.ui.view">
   <field name= "name">Pos_orders_filter</field>
   <field name= "model">pos.order</field>
   <field name="type">search</field>
   <field name="inherit_id" ref="point_of_sale.view_pos_order_filter"/>
   <field name= "arch" type= "xml">
     <xpath expr="/search/filter[1]" position="before">
       <filter string= "Today" name= "Today" domain = "[['date_order','>=',datetime.datetime.now().strftime('%d-%m-%Y 00:00:00')]]"/>
     </xpath>
  </field>
</record>
 
<record id= "pos_order_today" model= "ir.actions.act_window">
  <field name= "name">Today Order</field>
  <field name= "type">ir.actions.act_window</field>
  <field name= "res_model">pos.order</field>
  <field name= "view_type">form</field>
  <field name= "view_mode">tree</field>
  <field name= "context">{"Today":1}</field>
</record>

All the filters are in place in the respective model, but no one are set as default as should be.

I know I could simply set via front end but sometime when you deploy for a customer is hard to remember all you need to do.

Solved editing the 'context' field with:

<field name= "context">{"search_default_Today":1}</field>