Fixes so when a midi input from track or midi keyboard is played the keys shows being "pressed"
Have the editor be the only UI component to grab juce::MidiKeyboardState::Listener and it will then update each childen and then do a reprint.
The synth already handled multiple notes, but this change adds proper support so the 4 main UI components (Note Display, Rainbow Keyboard, Arc Spectrogram, and Generator Box) handles multiple notes being played at once
sjfricke
commented
2 years ago 
juce::MidiKeyboardState::Listenerand it will then update each childen and then do areprint.