title: OpenERP - field not showing in a tree view
body: <p>Here is my XML file. For some reason the field "product_uom" is not showing in view's tree view. Any insights why it is happening and how I can make it show?</p>
  
  <pre><code>&lt;tree string="Components" editable="bottom"&gt;
      &lt;field name="sequence" widget="handle"/&gt;
      &lt;field name="product_id" on_change="onchange_product_id(product_id, 
              product_qty)"/&gt;
      &lt;field name="type"/&gt;
      &lt;field name="product_qty"/&gt;
      &lt;field name="product_uom" on_change="onchange_uom(product_id, 
              product_uom)" groups="product.group_uom"/&gt;
      &lt;field name="product_rounding"/&gt;
      &lt;field name="product_efficiency"/&gt;
      &lt;field name="date_start"/&gt;
      &lt;field name="date_stop"/&gt;
      &lt;field name="attribute_value_ids" widget="many2many_tags" domain="
              [('product_ids.product_tmpl_id', '=', parent.product_tmpl_id)]"/&gt;
  &lt;/tree&gt;
  </code></pre>