title: How to make jstree empty on initialization?
body: <p>On click of a button I send some key to controllerand get my lists using json , the array inside my lists acts as my children in my jstree, </p>
  
  <pre><code> $("#btnSearch").on("click", function () {
          alert("I'm also here");
          $.ajax({
              type: "POST",
              url: "/Claims/JSTree",
              success: function (response) {
  
                  var clients = [];
                  var claimKeys = [];
                  $.each(response.ClientNames, function (i, item) {
                      clients.push(item);
                  });
                  alert(clients);
                  $.each(response.ClaimNumbers, function (i, item) {
                      claimKeys.push(item);
                  });
                  alert(claimKeys);
                  $('#FolderTree').jstree({
                      'core': {
                          'data': [
                             {
                                 'text': 'Client',
                                 'state': {
                                     'opened': false,
                                     'selected': false
                                 },
                                 'children': clients
                             },
                              {
                                  'text': 'Claim key',
                                  'state': {
                                      'opened': false,
                                      'selected': false
                                  },
                                  'children': claimKeys
                              },                               
                           ]
                      },
                      "plugins": ["checkbox"]
                  });
              }
          });
      });
  });
  </code></pre>
  
  <p>Everything works fine for the first time, when second time I pass a different key I get the lists, it even shows the values in alert, but my jstree still retains the previous values..Unless I stop and restart debugging, jstree doesn't become empty..Is there a way to empty jstree before populating it with children??</p>