JQuery draggable: scroll not working when helper: clone is used

Question

I have a folder list type of situation where I can drag items from one folder to another using jquery draggable/droppable. Folder items are draggable and folders are droppable. These are in a div that is small enough to show a vertical scroll bar.

I have "scroll: true" set on the draggable items so that they can cause the div to scroll. When I also use 'helper: "clone"' on the draggable items, the scrolling no longer works.

What am I doing wrong?

Here's some very simplified code:

<div style="background-color: red; width: 500px; height: 100px; overflow: auto;">

    <table id="nfTable" class="treeTable">
        <tr><td><span class="parent initialized expanded">drop here</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="draggable">drag me</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
        <tr><td><span class="droppable">drop here</span></td></tr>
    </table>

</div>
<script type="text/javascript" src="/js/jquery-1.3.2.min.js"></script>
// draggable and droppable in here:
<script type="text/javascript" src="/js/jquery-ui-1.7.2.custom.min.js"></script>
<script type="text/javascript">
$(function() {
    $(".draggable").draggable({
        // commenting the line below will make scrolling while dragging work
        helper: "clone",
        scroll: true,
        revert: "invalid"
    });

    $(".droppable").droppable({
        accept: ".draggable",
        drop: function(e, ui) {
            // todo
        }
    });
});
</script>

Answer 1

Try wrapping your overflow div with a div with position: relative; and adding position: relative; to your overflow div.

<div style="position: relative;">
    <div style="position:relative; background-color: red; width: 500px; height: 100px; overflow: auto;">
        <table id="nfTable" class="treeTable">
            <tr><td><span class="parent initialized expanded">drop here</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="draggable">drag me</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
            <tr><td><span class="droppable">drop here</span></td></tr>
        </table>
    </div>
</div>