title: Error: Non-assignable model expression: undefined (directive: childOne)
body: <p><strong>As a follow-up still regarding this plunker:</strong></p>
  
  <p><strong><a href="http://plnkr.co/edit/4SakSg6x5wuQQ5eYBwFN?p=preview">plunker</a></strong></p>
  
  <p><strong>If I review the console in Chrome when selecting an item in Child 1, I get the following error:</strong></p>
  
  <p>Error: Non-assignable model expression: undefined (directive: childOne)</p>
  
  <p>I am completely baffled as the directive element is an element, not an attribute and designated as such in the directive itself.</p>