in themes/kube/static/js/kube.js [1182:1191]
addActive: function(item)
{
item.$box.removeClass('hide').addClass('open');
item.$el.addClass('active');
if (item.$caret !== false) item.$caret.removeClass('down').addClass('up');
if (item.$parent !== false) item.$parent.addClass('active');
this.opts.currentItem = item;
},