partner-contact/base_continent/views/partner.xml

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

        <record id="res_partner_form_add_continent" model="ir.ui.view">
            <field name="name">res.partner.form.add_continent</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
                <field name="country_id" position="after">
                    <field name="continent_id"/>
                </field>
            </field>
        </record>

        <record id="view_res_partner_filter" model="ir.ui.view">
            <field name="name">res.partner.filter.add_continent</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_res_partner_filter"/>
            <field name="arch" type="xml">
                <group expand="0" position="inside">
                    <filter string="Continent" name="continent_groupby" context="{'group_by': 'continent_id'}"/>
                </group>
            </field>
        </record>

  </data>
</openerp>