@Override
 public void execute() {
   draggedResource = project.getResourceList().remove(draggedIndex);
   int dropIndex;
   if (row.isEmpty()) {
     dropIndex = row.getTreeTableView().getRoot().getChildren().size();
   } else {
     dropIndex = row.getIndex();
   }
   project.getResourceList().add(dropIndex, draggedResource);
 }
 @Override
 public void undo() {
   project.getResourceList().remove(draggedResource);
   project.getResourceList().add(draggedIndex, draggedResource);
 }