Update TODO.md

[manopapad]

No description provided.

[elliottslaughter]

I consider it a feature that you can scroll past the end of the profile. That allows to you e.g., center the end of the profile on your screen.

What might be a nice feature is making sure you can't scroll off the end of the profile so far that it's just not on screen at all.

[manopapad]

Fair enough, I'll adjust according to your comment. I would still like to have an indication what I'm looking at is not part of the profile, so I'm going to also suggest that out-of-bounds areas have a different background color.