There is already a very similar question BUT it is not the same as my question, hence the reason for my question:
Which DAW can handle simultaneous editing of MIDI channels / instruments per tracks?
Similar, but not the same, because that question details asks:
edit them as one unified track
My requirement is slightly different: I would like to be able to have several separate tracks open in the same window at once and be able to edit them all while they are open, to align notes etc. This would also include drum tracks. Each track would be per MIDI channel.
In the other answer, I've seen that some apps like Logic provide for editing multiple MIDI tracks but in one edit area(1). I would not want this because of the scenario where notes from one channel overlap another and so would be hard to edit, as can't see where the note underneath starts or finishes.
I had thought Ardour did what I want but it appears not: https://community.ardour.org/book/export/html/5937
There is no way currently to edit in note data for multiple regions at the same time, so for example you cannot select notes in several regions and then delete them all, nor can you copy-n-paste notes from one region to another.
Can Pro Tools First or Pro Tools do it?
Update
(1) Changed "edit window" to "edit area" - in text marked (1) above. I still want to do everything in one Window, i.e. without opening a separate window to edit a track. I want to be able to view all the piano roll bars, separately, per track from within one window, using vertical scroll bars for the window if necessary if a lot of tracks (and scroll bars within the tracks themselves if the notes cover many octaves) AND also be able to edit directly the content in these tracks displayed. Just by clicking on the content of the track to edit it. There should be a tool bar somewhere to select which tool for editing - e.g. note lengthener/shortener, note splitter, cut paste area of track. And so, the user can just click on any track and start editing right away, they can cut or copy a section of piano notes from one track to another, or also to the same track for repeated sections.