Unable to drop into empty sortable

https://github.com/rniemeyer/knockout-sortable/issues/23

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.22/jquery-ui.min.js"></script>
<script src="https://raw.github.com/rniemeyer/knockout-sortable/master/build/knockout-sortable.js"></script>
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.0.4/css/bootstrap.min.css">
<div data-bind="foreach: lists">
    <table class="table">
        <thead>
            <tr>
                <th>Name</th>
                <th>Desc</th>
            </tr>
        </thead>
        <tbody data-bind="sortable: {data: list}" style="height:20px">
            <tr>
                <td data-bind="text: name" ></td>
                <td data-bind="text: desc"></td>
            </tr>
        </tbody>
    </table>
</div>

JavaScript

///////////////////////////////
//create a draggable that is appropriate for dropping into a sortable
ko.bindingHandlers.drag = {
    init: function(element, valueAccessor, allBindingsAccessor)
    {
        //set meta-data
        ko.utils.domData.set(element, "ko_dragItem", valueAccessor());
        //combine options passed into binding (in dragOptions binding) with global options (in ko.bindingHandlers.drag.options)
        var options = ko.utils.extend(ko.bindingHandlers.drag.options, allBindingsAccessor().dragOptions);
        //initialize draggable
        $(element).draggable(options);
    },
    options:
    { 
        connectToSortable: "." + ko.bindingHandlers.sortable.connectClass,
        helper: "clone"
    }
};
//set up a receive handler for sortable that recognizes drag items
ko.bindingHandlers.sortable.options.receive = function(event, ui)
{
    var el   = ui.item[0];
    var item = ko.utils.domData.get(el, "ko_dragItem")
    var    draggable, targetParent, targetIndex;

    if (item)
    {
        targetParent = ko.utils.domData.get(this, "ko_sortList");
        draggable = $(this).children(".ui-draggable");
        targetIndex = draggable.index();
        
        if (targetIndex >= 0)
        { 
            targetParent.splice(targetIndex, 0, item);
            draggable.remove();
        }
    }
};
ko.bindingHandlers.flash = {
    init: function(element) {
        $(element).hide();
    },
    update: function(element, valueAccessor)
    {
        var value = ko.utils.unwrapObservable(valueAccessor());
        if (value)
        {
            $(element).stop().hide().text(value).fadeIn(function()
            {
                clearTimeout($(element).data("timeout"));
                $(element).data("timeout", setTimeout(function()
                {
                    $(element).fadeOut();
                    valueAccessor()(null);
                }, 3000));
            });
        }
    },
    timeout:...