bug in 'customize view' due to xpath

[yya (Axelor)]

we have inherited partner form view as follows:

<!--Partner-->
  <record id="partner_add_campaign_id" model="ir.ui.view">
   <field name="name">partner_add_campaign_id</field>
   <field name="model">res.partner</field>
   <field name="inherit_id" ref="axelor_oocrm.oocrm_partner_form_link_view"/>
   <field name="type">form</field>
   <field name="arch" type="xml">
                <xpath expr="/form/notebook/page/field[@name='account_id']" position="after">
           <separator string="Campaign" colspan="4"/>
                    <field name="campaign_id" nolabel="1" colspan="4"/>
                </xpath>
            </field>
        </record>

     <record id="oocrm_partner_campaign_address" model="ir.ui.view">
         <field name="name">oocrm.partner.campaign.link.address.field</field>
         <field name="model">res.partner</field>
         <field name="inherit_id" ref="axelor_oocrm.oocrm_partner_replace_form_view2"/>
         <field name="type">form</field>
         <field name="arch" type="xml">
          <xpath expr="//separator[@string='Contacts']" position="before">
           <separator string="Campaign" colspan="4"/>
           <field name="campaign_id" nolabel="1" colspan="4"/>
          </xpath>
        </field>
  </record>

first expression is adding campaign_id field in res.partner module i.e. main form

second expression is adding campaign_id field in one2many view of address-field in the same form (res.partner.address(address-field) is o2m in res.partner)

so form-view is working perfect but when trying to edit view from 'customize view' menu
it generates following error:

 /home/eiffel/workspace_django/Stable_Etiny/openerp/controllers/viewed.py in _inherit_apply(src=u'<?xml version="1.0" ?><form string="Partners">\n ...tebook></view></notebook>\n </form>', inherit=u'<?xml version="1.0"?>\n<xpath expr="//field[@name...e>\n\t\t\t\t\t</field>\n\t \t</xpath>\n \t', inherited_id=994)
  303 vnode.setAttribute('view_id', str(inherited_id))
  304 vnode.appendChild(node2)
  305 node.appendChild(vnode)
  306 else:
  307 attrs = ''.join([
node = <xml.dom.minidom.Document instance>, node.appendChild = <bound method Document.appendChild of <xml.dom.minidom.Document instance>>, vnode = <DOM Element: view>
 /usr/lib/python2.6/xml/dom/minidom.py in appendChild(self=<xml.dom.minidom.Document instance>, node=<DOM Element: view>)
 1550 and self._get_documentElement():
 1551 raise xml.dom.HierarchyRequestErr(
 1552 "two document elements disallowed")
 1553 return Node.appendChild(self, node)
 1554

<class 'xml.dom.HierarchyRequestErr'>: two document elements disallowed
      args = ('two document elements disallowed',)
      code = 3
      message = 'two document elements disallowed'