The mixer knob is really awkward to use with a mouse on the desktop app. I still haven't really figured out how I should move my mouse cursor to use it without accidentally jerking it around aimlessly, at least on piano.

Because I need to choose MIDI on every session, I sometimes forget to do that before I start playing. Practically every other MIDI software remembers the settings, Yousician does not. When I choose MIDI when inside a song already the mixer is at full volume regardless what I've done before with it, and I need to tweak the knob to zero because I'm ont using Yousician generated sounds. It's quite annoying to begin with, and the knob feels like it's just playing games with me.

Why not just make it work like those knobs work in any other software - click it and drag up to increase, drag down to decrease.