Measure lines?

[Edgehopper]

So, I'm looking at this screenshot:

http://medialib.computerandvideogames.com/screens/screenshot_181335.jpg

And I see that where Guitar Hero had clearly marked lines counting time, only the left track has those lines here. I hope that's just an early build thing? One of the things I strongly prefer about Guitar Hero over other music games is the ability to know when a note comes in the rhythm without guesswork, because time is so clearly marked on the fretboard. Particularly for expert drum parts, I don't see how it could work without lines marking time.

[bdurk15]

My guess is that the purple one on the left is the one that the player is using, as opposed to the other players online or whatnot. That might explain why it's a different color, and why it's the only one with measure bars. That way you can see what your buddies are doing, but also not be distracted with the level of detail of their parts.