title: How to get rid of the extra line on jstree's root node
body: <p>As you can see on the screenshot from a jstree,above the triangle on the first node there is an extra vertical dash line:</p>
  
  <p><img src="https://i.stack.imgur.com/zdoRr.png" alt="enter image description here"></p>
  
  <p>Anybody knows how to get rid of it?</p>