in realtà questo
<record id="action_partner_customer_form" model="ir.actions.act_window">
<field name="res_model">res.partner</field>
<field name="inherit_id" ref="base.action_partner_customer_form"/>
<field name="arch" type="xml">
<field name="context" position="replace">
<field name="context">{'default_customer':1, 'search_default_customer':1, 'search_default_category_id':1}</field>
</field>
</record>
deve diventare
<record id="action_partner_customer_form" model="ir.actions.act_window">
<field name="res_model">res.partner</field>
<field name="inherit_id" ref="base.action_partner_customer_form"/>
<field name="arch" type="xml">
Xpath
<field name="context" position="replace">
<field name="context">{'default_customer':1, 'search_default_customer':1, 'search_default_category_id':1}</field>
</field>
Xpath
</field>
</record>
dove la dicitura xpath vuol dire che li ci devi mettere il percorso in cui vuoi aggiungere i field della vista che stai ereditando
ciao