sale_view.xml

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

    <record id="view_quotation_tree" model="ir.ui.view">
      <field name="name">sale.order.tree</field>
      <field name="model">sale.order</field>
      <field name="inherit_id" ref="sale.view_quotation_tree" />
      <field name="arch" type="xml">
        <field name="user_id" position="after">
          <field name="department_id" />
        </field>
      </field>
    </record>

    <record id="view_order_tree" model="ir.ui.view">
      <field name="name">sale.order.tree</field>
      <field name="model">sale.order</field>
      <field name="inherit_id" ref="sale.view_order_tree" />
      <field name="arch" type="xml">
        <field name="user_id" position="after">
          <field name="department_id" />
        </field>
      </field>
    </record>

    <record id="view_order_form" model="ir.ui.view">
      <field name="name">sale.order.form</field>
      <field name="model">sale.order</field>
      <field name="inherit_id" ref="sale.view_order_form" />
      <field name="arch" type="xml">
        <field name="user_id" position="after">
          <field name="department_id" widget="selection"/>
        </field>
      </field>
    </record>

    <record id="view_sales_order_filter" model="ir.ui.view">
      <field name="name">sale.order.list.select</field>
      <field name="model">sale.order</field>
      <field name="inherit_id" ref="sale.view_sales_order_filter" />
      <field name="arch" type="xml">
        <xpath expr="//filter[@string='Salesperson']" position="after">
          <filter string="Department" icon="terp-folder-orange" domain="[]" context="{'group_by':'department_id'}"/>
        </xpath>
        <field name="partner_id" position="after">
          <field name="department_id"  widget="selection"/>
        </field>
      </field>
    </record>

  </data>
</openerp>