There are notches there now but I'm not sure if they actually mean anything. It would be nice to have it show db so it would allow us to see at a glance where to set comp and limiter thresholds. This would be a nice touch.
When carrying out a bounce or commit action the popup window could also display the bus sources selected. It would add confidence when doing a bounce or commit that the correct sources have been chosen and be a way for the user to make sure they are bouncing/commiting the right thing.