Piano roll editor - availability and features MU4

I gather that as yet there is no piano roll editor in MU4.

Also, as far as I can see, the PRE in MU3 only works on staves for one instrument. It is sometimes useful to be able to see all the notes in a score in PRE format. If nothing else it provides a very graphical way to see the range of instrumentation, and also whether chords are in open or closed format.

It would be very helpful if a PRE which worked over a whole score could be implemented, though that wouldn't preclude individual instruments having their own PRE formats.