iPad Smart Lock
I am not a fan of Apple but my wife has an iPad with the following problem.
Up until recently the Smart Lock function worked well, the screen went blank when the cover was folded over the screen, and when the cover was re-opened the home screen lit up and the slide bar had to be used to get started.
Now, after an update, it no longer works. Folding the cover over the screen does nothing and the screen stays lit unless you manually switch the thing off. Some sites suggest there is an option in the Settings-General menu, but I cannot see anything that mentions Smart Lock activation.