anchor.diff:  
     // The master component that manages both tables and
     // the add/remove actions
  -  GroupsManager = React.createClass({
  +  var GroupsManager = React.createClass({
       getInitialState: function() {
         return {
           students: [],
  
positive.code:   });
  
    // The table of groups on the right.
    GroupsTable = React.createClass({
      groupCheckboxClicked: function(event) {
        var value = event.currentTarget.checked;
        var group_id = parseInt(event.currentTarget.getAttribute('id'));
  
negative.code:   });
  
    // Table of students, on the left.
    var GroupsStudentsTable = React.createClass({
      checkboxClicked: function(event) {
        var value = event.currentTarget.checked;
        var student_id = parseInt(event.currentTarget.getAttribute('id'));
  