Update Background Color of Checkbox in PySimpleGuiQT

Question

Im trying to update the background color of my checkbox when it is clicked. However, the moment i call the update method, somehow another event on the same element is triggered, resulting in unexpected behavior. Can somebody tell me how to achieve that?!

My minimal Code is as follows:

import PySimpleGUIQt as sg

layout = [
    [sg.Checkbox('test', enable_events=True, key='test', background_color="green",default=True)]
]

window = sg.Window('Sample GUI', layout, finalize=True)
while True:  # Event Loop
    event, values = window.read(timeout=100)
    if event == sg.WINDOW_CLOSED:
        break
    elif event == "test":
        if not values[event]:
            window[event].update(background_color="red")
        else:
            window[event].update(background_color="green")

window.close()