private void attachEventHandlers() {
if (fileTreeUiController == null) {
return;
}
fileTreeUiController.setFileTreeNodeMoveListener(new DragDropListener() {
@Override
public void onDragDrop(FileTreeNode node, JsDragEvent event) {
event.getDataTransfer().clearData(MOVE_START_INDICATOR_FORMAT);
if (isReadOnly || !wasDragInTree(event)) {