title: Odoo - prevent button from closing wizard
body: <p>I have a transient model that serves as a dialog. In my form view I have a button like this:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;footer states="partnerId"&gt;
     &lt;button name="check_tax_id" string="Tovább" type="object"/&gt;
  &lt;/footer&gt;
  </code></pre>
  
  <p>The button invokes this function (I can confirm it actually invokes):</p>
  
  <pre class="lang-python prettyprint-override"><code>@api.one
      def check_tax_id(self, context=None):
          self.state = "partnerDetails"
  
          return None;
  </code></pre>
  
  <p>My problem is that the dialog window is closed immediately once I click this button!
  What am I doing wrong?</p>