The keyboard in the doozzoo apps is a beta version. (-> Deutsche Anleitung)
A simple harpsichord sound serves primarily as an aid for theory and ear training lessons.
The keyboard can be operated with the mouse or played with the computer keyboard.
KEY ASSIGNMENT ON THE COMPUTER KEYBOARD:
You can switch off the computer keyboard with the switch in the upper right corner.
The computer keyboard is on by default.
Thus, the computer keyboard is turned off: