New Post: Why did you implement a different behaviour in XSSFWorkbook and HSSFWorkbook?

tonyqus wrote:

It's just a increasing region index. It's possible that there are many regions so that this method will return 0, 1, 2, 3. It's normal.

Of course It's normal to increasing index. It's not normal to start from zero in HSSDSheet.AddMergedRegion(region) and from 1 in XSSDSheet.AddMergedRegion(region).
And you didn't answer about converting Color to short.