Scroll propierty of a draggable object does not work as expected when is set to a scrolleable div.
If you have a <div>(with style="overflow:auto"), that contains a sortable list, and that list is so long that makes the <div> to have a scrollbar, and you scroll down to see the lower elements, and try to dragg and drop that elements, the dragged elements suffers an offset(proportial to the scroll offset) and is impossible to drop it on the lower positions of the sortable list.
Simple example attached, tested on Firefox and Konqueror.
<html>
<head>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/MochiKit.js"></script>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/New.js"></script>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/Visual.js"></script>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/Signal.js"></script>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/DragAndDrop.js"></script>
<script type="text/javascript" src="/js-devel/mochikit/MochiKit/Sortable.js"></script>
</head>
<body>
<div id=main style="width:300px;height:300px;overflow:auto">
<div id="1" style="padding:20px">
i'm the div 1
</div>
<div id="2" style="padding:20px">
i'm the div 2
</div>
<div id="3" style="padding:20px">
i'm the div 3
</div>
<div id="4" style="padding:20px">
i'm the div 4
</div>
<div id="5" style="padding:20px">
i'm the div 5
</div>
<div id="6" style="padding:20px">
i'm the div 6
</div>
<div id="7" style="padding:20px">
i'm the div 7
</div>
<div id="8" style="padding:20px">
i'm the div 8
</div>
<div id="9" style="padding:20px">
i'm the div 9
</div>
</div>
<script type="text/javascript">
MochiKit.Sortable.Sortable.create('main', {tag:'div',scroll:'main'});
</script>
</body>
</html>
