title: Change the layout of a TreeView to looks like multiple ListBox
body: <p>I'm trying to change the layout of a databound treeview from this:</p>
  
  <p><a href="https://i.stack.imgur.com/Xbt1F.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Xbt1F.png" alt="alt text"></a>
  </p>
  
  <p>To this:</p>
  
  <p><a href="https://i.stack.imgur.com/pW81h.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pW81h.png" alt="alt text"></a></p>
  
  <p>And of course selection must works properly:</p>
  
  <p><a href="https://i.stack.imgur.com/8BivJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8BivJ.png" alt="alt text"></a></p>
  
  <p>Do you have any ideas about how to do that. I've been trying to change the template but I can't find out a way to have this behavior. Maybe a component already exists...</p>
  
  <p>Thanks for your help !</p>