private TreeViewer fViewer;
public static void addDragAndDropSupport(TreeViewer viewer) {
int dndOperations = DND.DROP_COPY | DND.DROP_MOVE | DND.DROP_LINK;
Transfer[] transfers = new Transfer[]{ObjectTransfer.getInstance()};
viewer.addDragSupport(dndOperations, transfers, new ViewerDragAdapter(viewer));
viewer.addDropSupport(dndOperations, transfers, new ViewerDropAdapter(viewer, new XMLDragAndDropManager(viewer)));
}