gistfile1.js

    var selectedEvents = {};
    $scope.isSelected = ƒ(event) {
      return selectedEvents[event.client.name + '_' + event.check.name];
    }
    $scope.selectEvent = ƒ($event, event) {
      if (selectedEvents[event.client.name + '_' + event.check.name]) {
        selectedEvents[event.client.name + '_' + event.check.name] = false;
      } else {
        selectedEvents[event.client.name + '_' + event.check.name] = true;
      }
      $event.stopPropagation();
    }