title: 3-state "expanded", "collapsed" and "semi-expanded" tree control
body: <p>What I'm trying to do is have a 3 state tree expansion.</p>
  
  <p>I have three different icons for "expand" "collapse" "semi-expanded" which I want to use to show a partially populated tree control with all nodes initialized to semi-expanded state and then on clicking the "semi-expanded" icon it gets data from server and populates the tree and open that branch with "expanded" icon.</p>
  
  <p>I tried looking for it but couldn't find anything close to it except the 3-state checkbox but don't know how to use it on 3 state icon when tree would only maintain 2 states.</p>
  
  <p>Thanks in advance.</p>