GNOME settings pages don't have "apply" buttons. When do you think a selection from a drop-down or numerical selector takes effect?
Yes, most settings now take effect immediately, and that's great. (I think KDE still prefers a separate "apply" step though). That is (still) separate from the decision of how to style something which turns something on and off, which is what I'm complaining about. I don't take any issue with having things apply immediately.
You raise visual impairment, which is exactly why I'm complaining. Look at the image and tell me, which of the controls is on, and which is off?
