title: Field not hiding from tree view using Fields_view_get
body: <p>I have written a code to update my treeview according to input. it is basically working using <code>context</code>. My fields_view_get method is like this:</p>
  
  <pre><code>def fields_view_get(self,cr,uid,view_id=None,view_type='form',context=None, toolbar=False, submenu=False):
      if context is None:
          context={}
      res=super(product_product,self).fields_view_get(cr,uid,view_id=view_id,view_type=view_type,context=context,toolbar=toolbar,submenu=submenu)
      doc=etree.XML(res['arch'])  
      if context.get('parent',False):
          parent=context.get('parent',False)
          if parent==85: ####Vehicle
          print etree.tostring(doc,pretty_print=True)
              for node in doc.xpath("//field[@name='size_furn']"):
              node.set('invisible','1')
              res['arch']=etree.tostring(doc)
      print "\n\n\n\nxml ",res['arch']
      return res
  </code></pre>
  
  <p>Here i am updating visibility of <code>size_furn</code></p>
  
  <p>I have printed output on console. here is <code>res['arch']</code> before change </p>
  
  <pre><code>&lt;tree colors="red:  state in ('draft', 'end', 'obsolete');black: state not in ('draft', 'end', 'obsolete')" string="Asset Products"&gt;
  
                  &lt;!--    &lt;field name="default_code"/&gt; --&gt;
                      &lt;field name="name" modifiers="{&amp;quot;required&amp;quot;: true}"/&gt;
                  &lt;!-- ############################################################ --&gt;
                      &lt;field name="product_code" modifiers="{&amp;quot;readonly&amp;quot;: true}"/&gt;
                  &lt;!-- ############################################################   --&gt;
   &lt;field name="state" invisible="True" modifiers="{&amp;quot;tree_invisible&amp;quot;: true}"/&gt;
  &lt;field name="size_furn" invisible="0" modifiers="{&amp;quot;tree_invisible&amp;quot;: false}"/&gt;
                  &lt;/tree&gt;
  </code></pre>
  
  <p>here is the changes on <code>res['arch']</code></p>
  
  <pre><code>&lt;tree colors="red:  state in ('draft', 'end', 'obsolete');black: state not in ('draft', 'end', 'obsolete')" string="Asset Products"&gt;
  
                  &lt;!--    &lt;field name="default_code"/&gt; --&gt;
                      &lt;field name="name" modifiers="{&amp;quot;required&amp;quot;: true}"/&gt;
                  &lt;!-- ############################################################ --&gt;
                      &lt;field name="product_code" modifiers="{&amp;quot;readonly&amp;quot;: true}"/&gt;
                  &lt;!-- ############################################################   --&gt;
   &lt;field name="state" invisible="True" modifiers="{&amp;quot;tree_invisible&amp;quot;: true}"/&gt;
  &lt;field name="size_furn" invisible="1" modifiers="{&amp;quot;tree_invisible&amp;quot;: false}"/&gt;
                  &lt;/tree&gt;
  </code></pre>
  
  <p>As we can see xml is updating, but problem is changes are not visible on openerp application. I can view this field in any case. i tried to use <code>True</code> and <code>False</code> too. but it didnot work. any way to resolve this issue.</p>
  
  <p>Thanks</p>