User-keys for n notes

Enhancement Summary

Let user allocate a collection of notes to one user selected key

Justification

Creative inhancement

Mockup

The idea is to let user allocate n notes to a user-specified key. I imagine the num-keys on PC-boards, and on MIDI-KBs user could allocate the highest registers.
The UI should be a new page on piano-roll. I have named it 'Capture'. Red is used to emphasize that this is a type of 'recording'.
In the picture the selected note-stack is a chord. After clicking a red diamond, the user is prompted to select a key on his hardware.

Lets say he select "num-lock" LMMS would now treat a press on num-lock as any pressed key, but all the allocated notes would play, and in capture mode,

all the allocated notes would be captured.
The user should be able to build i notes in collections, allocated to j HW-keys.
(some advanced MIDI-KB already got this -btw)

No files, tests, or entry points are named. Start by locating the piano-roll UI and MIDI/keyboard input handling, then determine how note collections, user-selected hardware keys, and capture mode fit together; done means the proposed Capture page can assign note groups to keys and play or capture them as described.