Aim Assist line should span the screen when using two PRVs in split screen

[Christian Jones 799]

Say you have a horizontal split screen workflow going consisting of two PRV views, like piano on one and bass or drums on the other.. it'd be nice if that Aim Assist line you call up when pressing "X" would span across both PRVs and not just the one that's in focus. This would help for lining things up across the two PRVs--like if you're trying to line up drums especially w/ some other midi data on another PRV--w/o having to place the Now Time there to do it.