It might be easy, but it is also very subtle and not very noticable. I guess a good syntax highlighter could solve that, but it looks like something that would be easy to overlook while debugging.

I comment out blocks very quickly using my editor. In Vim I just cursor to the { or the }, then hit Shift-V % .c and the entire block is commented. To uncomment, use the same procedure except use .C instead of .c.

The .c command is provided by the BlockComment plugin found here. The Shift-V starts line by line highlighting and the % finds the matching bracket to the one you are currently on or near. You could probably write a simple macro that does the same thing in one or two keypresses as well.

- Cees