product_variant_inactive/product_variant_view.xml

<openerp>
  <data>

    <record model="ir.ui.view" id="view_stock_product_tree">
        <field name="model">product.product</field>
        <field name="inherit_id" ref="stock.view_stock_product_tree"/>
        <field name="arch" type="xml">
            <!-- Add grey color for inactive record.
                 Variants are mainly used with stock, 
                 Then we also embedds color attributes of module stock -->
            <xpath expr="//tree" position="attributes">
                <attribute name="colors" translation="off">grey:active==False;red:virtual_available&lt;0;blue:virtual_available&gt;=0 and state in ('draft', 'end', 'obsolete');black:virtual_available&gt;=0 and state not in ('draft', 'end', 'obsolete')</attribute>
            </xpath>
        </field>
    </record>


    <record model="ir.ui.view" id="detail_field_custom_in_view">
        <field name="model">product.product</field>
        <field name="inherit_id" ref="product.product_product_tree_view"/>
        <field name="arch" type="xml">
            <xpath expr="//tree" position="inside">
                <field name="active" invisible ="1"/>
                <button type="object" name="button_activate" invisible="1"
                        attrs="{'invisible': [('active','=',True)]}" icon="gtk-stop"/>
                <button type="object" name="button_deactivate" invisible="1"
                        attrs="{'invisible': [('active','=',False)]}" icon="gtk-apply"/>
            </xpath>
        </field>
    </record>
    <record id="product.product_variant_action" model="ir.actions.act_window">
        <field name="context">{'search_default_product_tmpl_id': [active_id], 
                               'default_product_tmpl_id': active_id, 
                               'active_test': False}</field>
    </record>

  </data>
</openerp>