Remove `var` declaration---this variable is already delcared as an argument

		});

		lastChecked = null;

		$(actionCheckboxes).click(function(event) {

			if (!event) { var event = window.event; }

			if (!event) { event = window.event; }

			var target = event.target ? event.target : event.srcElement;

			if (lastChecked && $.data(lastChecked) != $.data(target) && event.shiftKey == true) {

				var inrange = false;