public static @NotNull ActionCallback moveDown(final @NotNull JTree tree) {
    final int size = tree.getRowCount();
    int row = tree.getLeadSelectionRow();
    if (row < size - 1) {
      row++;
      return showAndSelect(tree, row, row + 2, row, getSelectedRow(tree), false, true, true);
    } else {
      return ActionCallback.DONE;
    }
  }
public static @NotNull ActionCallback moveDown(final @NotNull JTree tree)