containers` by default
            },
            invalid: function (el, handle) {
                return false; // don't prevent any drags from initiating by default
            },
            direction: 'vertical',             // Y axis is considered when determining where an element would be dropped
            copy: false,                       // elements are moved by default, not copied
            copySortSource: false,             // elements in copy-source containers can be reordered
            re