I have developed a UI with features of Drag and drop from RadGridView to RadTreeView, it worked perfectly in old version (2011 Q3), after I upgraded to new version (2014 Q4), I got a warning message for the RadDragAndDropManager because of obsolete and the drag & drop cannot work now. My question is whether I must upgrade RadDragAndDropManager to DragDropManager suggested by some articles, or I still can use the RadDragAndDropManager without affecting the exsiting features.
Please refer to attachment for details.