title: Odoo doesn't show the field label in xpath
body: <p>I'm adding a custom string field (stock_value) to the 'product.supplierinfo' module in Odoo enterprise 11 but I can't get it to display the label correctly. </p>
  
  <p>I inherited the module and then added a new field to the module and to the view trough xpath.</p>
  
  <p><strong>Problem:</strong> the string related to the new field is not shown.</p>
  
  <p><strong>Module:</strong></p>
  
  <pre><code>class class_name(models.Model):
      _inherit                        = 'product.supplierinfo'
      stock_value                     = fields.Integer(string="Stock")
  </code></pre>
  
  <p><strong>View:</strong></p>
  
  <pre><code>&lt;!-- Stock value in the vendors --&gt;
  &lt;record id="view_product_product_supplierinfo_form_view" model="ir.ui.view"&gt;
      &lt;field name="name"&gt;product.supplierinfo.product.form&lt;/field&gt;
      &lt;field name="model"&gt;product.supplierinfo&lt;/field&gt;
      &lt;field name="inherit_id" ref="product.product_supplierinfo_form_view"/&gt;
      &lt;field name="arch" type="xml"&gt;
      &lt;xpath expr="//field[@name='price']" position="after"&gt;
          &lt;field name="stock_value" /&gt;
      &lt;/xpath&gt;
      &lt;/field&gt;
  &lt;/record&gt;
  </code></pre>
  
  <p><strong>Result:</strong> as you can see theres a zero bellow the price value but the string label 'Stock' is not shown.</p>
  
  <p><a href="https://i.stack.imgur.com/QzIey.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QzIey.png" alt="enter image description here"></a></p>
  
  <p><strong>Other thing is tried:</strong></p>
  
  <p>Adding the next code:</p>
  
  <pre><code>&lt;separator /&gt;
  &lt;label for="stock_value" string="Stock Value"/&gt;
  </code></pre>
  
  <p>Gives me</p>
  
  <p><a href="https://i.stack.imgur.com/bcdLe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bcdLe.png" alt="enter image description here"></a></p>
  
  <p>Putting the field inside a group gives me</p>
  
  <p><a href="https://i.stack.imgur.com/IrkQX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IrkQX.png" alt="enter image description here"></a></p>
  
  <p>I also tried changing the position to 'before' in this last view but I cannot manage to make it look as it should. I tried using @string but that no longer works.</p>
  
  <p>Thank you in advantage for your help.</p>