Unnecessary black window appears when using Kivy and Multiprocessing about kivy HOT 2 CLOSED

This is a problem with the way multiprocessing works in python, and the way kivy works. Here is a multiprocessing example using kivy: https://github.com/ElliotGarbus/MidiClockGenerator
Take a look at main.py, notice that most of the code is under a gate: "if name == 'main':"
This ensures that only the main processes creates a Window. The import of kivy.app creates a window, so that needs to be under a gate.
This is discussed briefly in the python docs. https://docs.python.org/3/library/multiprocessing.html#multiprocessing-programming
Read the section titled: "Safe importing of main module"

from kivy.

Duplicate of #8340 and #4744

from kivy.