You have to create your custom tree view in your custom module and then inherit the applicant's view and then add attribute context="{'tree_view_ref': 'your_tree_view_id'}" in context (partner_id) field.

Like this:

<record id="inherit_view_partner_tree" model="ir.ui.view">
    <field name="name">res.partner.inherit.tree</field>
    <field name="model">res.partner</field>
    <field eval="8" name="priority"/>
    <field name="arch" type="xml">
        <tree string="Contacts">
            <field name="name"/>
            <field name="phone"/>
            <field name="email"/>
            <field name="street"/>
            <field name="country_id"/>
        </tree>
    </field>
</record>

<record id="inherit_crm_case_form_view_job" model="ir.ui.view">
    <field name="name">Jobs - Recruitment Form</field>
    <field name="model">hr.applicant</field>
    <field name="inherit_id" ref=" hr_recruitment.crm_case_form_view_job "
        <field name="partner_id" position="attributes">
            <attribute name="context">{'tree_view_ref': 'inherit_view_partner_tree'}</attribute>
        </field>
    <field
</record>

I have the same problem and I got the answer:

eg:

create a custom tree view:

    product.product.tree.ist

    product.product

then:

    {'tree_view_ref': 'your_custom_module_name.sale_line_product_search_more_tree_view'}

Hi, Im having a similar problem, could you fix it??