When an entire block of code is commented out with the /* */ characters, SQL Compare only shows only the lines with these characters as changed. It does not show the unchanged block of code between them as changed, even though the impact of commenting out this code can indeed be a significant change.

I suggest that unchanged lines of code enclosed by /* */ around it should still show as a substantive change. When we recently deployed an SP update with a large block of code that was commented out during testing, it slipped in because the scrolling view that shows where the changes are registered very small changes and it was overlooked.