I tried updating the .dll and it still did not work (my sheets are still visible). I have attached a sample console app which demonstrates the issue.
Thanks for your posting and using Aspose.Cells.
We were able to observe this issue using your sample code and source files. We have logged this issue in our database. We will look into it and fix the issue. Once the issue is resolved or we have some other update for you, we will let you know asap.
This issue has been logged as CELLSNET-41700.
Thanks for your posting and using Aspose.Cells for .NET.
After investigation, we found that your macro code makes the worksheet visible again. Please check your macro