New Post: Display newest worksheet on Workbook Open

Another question regarding NPOI 2.1.3: When I add a new page to an existing workbook, I want that new page to be the first one my user sees when the newly-updated workbook opens in Excel. I've tried using "sheet1.SetActive(true)", but that doesn't do it. Am I using the method incorrectly, or is there another way?

I've tried using .SetActive() immediately after .CreateSheet(), and immediately before workbook.Write(filestream).