Combining jQuery UI selectable and draggable

selectable-draggable.js

$(function () {
	'use strict';
	var selected = $([]), offset = {top: 0, left: 0};
	$("#container").selectable();
	$("#container div").draggable({
		snap : true,
		start: function () {
			if (!$(this).is(".ui-selected")) {
				$(".ui-selected").removeClass("ui-selected");
			}
			selected = $(".ui-selected").each(function () {
				var element = $(this);
				element.data("offset", element.offset());
			});
			offset = $(this).offset();
		},
		drag: function (event, ui) {
			var draggedTop = ui.position.top - offset.top, draggedLeft = ui.position.left - offset.left;
			selected.not(this).each(function () {
				var element = $(this), off = element.data("offset");
				element.css({top: off.top + draggedTop, left: off.left + draggedLeft});
		    });
		}
	});
});