Need to take certain mouse path for drop to work in a sortable with scrollbar!

Question

Hi,

I have a drag and drop to a sortable setup like this:

<table width="500px" height = "400px">
    <tr>
        <td valign="top" width="50%">
            <ul id="target">
            </ul>
        </td>

        <td valign="top" width="50%">
            <ul id="source">
            </ul> 
        </td>
    </tr>
</table>

so the items in #source are made draggable and can be dropped into #target. It works fine until the vertical height of #target grows enough to show a scroll bar. When this happens, drags across the scrollbar track thumb seem to be causing confusion - the drops no longer work. I have to drag the items down and around the scroll bar, then sneak in from the bottom for the drop to register and work.

Is there some general setting I'm missing that could be causing that? Everything is default as in the examples. The table is in a jquery dialog class.

Thanks