Drag Drop of webparts functionality is not working in Moss 2007

In Moss 2007, most of the times we want to move the added webparts from one webpart zone to another webpart zone by drag and drop. But sometimes, this functionality is missing in moss 2007 customised pages. The solution of this problem is to add the script to the master page of the site.

Refer to the below image :

Add the script between the <WePartPages:SPWebPartManager> and <form> tag.

        <script language="javascript" type="text/javascript">
            function MSOLayout_GetRealOffset(StartingObject, OffsetType, EndParent)
            {
                var realValue=0;
                if (!EndParent) EndParent=document.body;
                for (var currentObject=StartingObject; currentObject && currentObject !=EndParent && currentObject != document.body; currentObject=currentObject.offsetParent)
                {
                    var offset = eval('currentObject.offset'+OffsetType);
                    if (offset) realValue+=offset;
                }
                return realValue;
            }
        </script>