The on-screen keyboard combines a note selector and a root note selector.
A common interaction is to select a combination of notes, then shift the root note up and down as you perform.
In the note selector you can toggle notes on and off. Up to 12 notes can be activated at the same time.
If you select a new note, now two notes are activated. If you click on an activated note, it is now deactivated.
If you run your finger along the keyboard, any unactivated notes will be activated as your finger crosses that note, and will remain activated until you switchthem off.
Using a two finger scroll gesture horizontally, you can move across the keyboard horizontally.