title: vis.js hierarchical network graph layout
body: <p>I've found this strange layout in hierarchical network graph by using vis.js.
  As you can see, the edges are messed up.
  Any suggestion would be nice. Thanks.
  Or is it possible to change the sort function by the parent node position?</p>
  
  <h3>Figure 1: The current network</h3>
  
  <p><a href="https://i.stack.imgur.com/il5EM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/il5EM.png" alt="enter image description here"></a></p>
  
  <h3>Figure 2: The expected network</h3>
  
  <p><a href="https://i.stack.imgur.com/6yXIE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6yXIE.png" alt="enter image description here"></a></p>