code: function (event) {
        var $toggleBtn = $(event.target);
        var $descWrapper = $toggleBtn.parent().next();
        var $descendants = $descWrapper.find('.node');
        var $children = $descWrapper.children().children('.node');
        if ($children.is('.sliding')) { return; }
        $toggleBtn.toggleClass('fa-plus-square fa-minus-square');
        if ($descendants.eq(0).is('.slide-up')) {
          $descWrapper.removeClass('hidden');
          this.repaint($children.get(0));
          $children.addClass('sliding').removeClass('slide-up').eq(0).one('transitionend', { 'vNodes': $children }, this.expandVNodesEnd);
        } else {
          $descendants.addClass('sliding slide-up').eq(0).one('transitionend', { 'vNodes': $descendants }, this.collapseVNodesEnd);
          $descendants.find('.toggleBtn').removeClass('fa-minus-square').addClass('fa-plus-square');
        }
      }
docs: event handler for toggle buttons in Hybrid(horizontal + vertical) OrgChart