partner-contact/partner_relations/view/res_partner.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
    <data>

        <record id="view_res_partner_filter" model="ir.ui.view">
            <field name="name">partner_relations.view_partner_filter</field>
            <field name="inherit_id" ref="base.view_res_partner_filter" />
            <field name="model">res.partner</field>
            <field type="xml" name="arch">
                <data>
                    <field name="parent_id" position="after">
                        <field name="search_relation_partner_id" />
                        <field name="search_relation_id" />
                        <field name="search_relation_date" />
                        <field name="search_relation_partner_category_id" />
                    </field>
                </data>
            </field>
        </record>

        <record id="view_partner_form" model="ir.ui.view">
            <field name="name">partner_relations.view_partner_form</field>
            <field name="inherit_id" ref="base.view_partner_form" />
            <field name="model">res.partner</field>
            <field type="xml" name="arch">
                <xpath expr="//div[@name='buttons']" position="inside">
                    <button class="oe_inline oe_stat_button"
                            type="action"
                            context="{
                                'search_default_this_partner_id': active_id,
                                'default_left_partner_id': active_id,
                                'active_model': 'res.partner',
                                'active_id': id,
                                'active_ids': [id],
                                'active_test': False,
                            }"
                            name="%(action_res_partner_relation_all)d"
                            icon="fa-users">
                        <field string="Relations" name="relation_count" widget="statinfo"/>
                    </button>
                </xpath>
            </field>
        </record>

        <act_window id="action_show_partner_relations"
            name="Show partner's relations"
            src_model="res.partner"
            res_model="res.partner.relation.all"
            domain="[('this_partner_id', 'in', active_ids)]"
            key2="client_action_multi" />

    </data>
</openerp>