save xlsx file then use excel open has issue

[mankaixin]

when only load a xlsx then do nothing。
Using excel open has some quesion

  void test_Load_save()
  {
      xlnt::workbook wb;
      wb.load(path_helper::test_file("3.xlsx"));
     // xlnt::workbook wb2;
     // wb2.copy_sheet(wb.active_sheet());
      wb.save(path_helper::test_file("2.xlsx"));
  }

2.xlsx

3.xlsx