For those that are not super musically inclined, it would be useful to have a quick toggle to restrict note entry to a preset scale and key to keep things in tune easily without guesswork, and to disable it in case the user is inputting non-melodic notes or for playing out of key.
What is the problem?
On the original Polyend Tracker, you could set the pads to a specific musical key and scale, which would allow users to keep music in key easily, and they could easily nudge notes if they wanted them out of key. On the Tracker Mini, obviously the pads don’t exist, and the +/- buttons only move the note in preset increments. This may make it harder for users with less musical experience to easily keep their music in key.
What do you want to achieve?
Enable settings/toggle to set a musical key lock for note entry.
Are there any workarounds?
Get better at music theory? 
Sarcasm aside, there are no workarounds at this time.
Any links to related discussions?
None that I could find.
Any references to other products?
Original Polyend Tracker