Gnome black screen

with the help of some gnome-shell extensions I customized the screen display to be black(empty!) completely(no background, no icons, no nothing, hiding everything).
Unfortunately, Gnome Extensions Application loads updates of installed extensions in the background?
Extensions-Updates destroy the blank screen sometimes.
(for example: recently caused by an update of Night Theme Switcher)
Can someone tell me how to stop this automaton?
(does switch-off notifications of Extensions help?)