title: Ext JS - Bind multiple formfields to one field of the model
body: <p>I have a model with a hex color field. The user can edit it as rgb via 3 separate numberfields. I'm trying to bind the field to these components but I'm not sure how to do it. I tried putting them in a container and binding the container to the field. However my setValue isn't called when a numberfield is changed.</p>
  
  <p>I guess I could add listeners to the numberfields but I was hoping there was a better way to go about it.</p>
  
  <p><a href="https://fiddle.sencha.com/#view/editor&amp;fiddle/23t2" rel="nofollow noreferrer">https://fiddle.sencha.com/#view/editor&amp;fiddle/23t2</a></p>