crm_opportunity_tree/crm_opportunity_tree.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
  <data>
    <record model="ir.ui.view" id="crm_case_tree_view_oppor_inherit3">
        <field name="name">Opportunities Tree Inherit3</field>
        <field name="model">crm.lead</field>
        <field name="inherit_id" ref="crm.crm_case_tree_view_oppor"/>
        <field name="arch" type="xml">
            <data>
                <field name="create_date" position="after">
                    <field name="date_last_stage_update"/>
                </field>
                <field name="country_id" position="replace">
                        <field name="country_id"  invisible="1"/>
                </field>
            </data>
          </field>
    </record>
  </data>
</openerp>