Small question about the Mojave update (and the F3 key)?

I've just recently updated to Mojave, and noticed one pretty big change...

Before the update, I could stick my cursor in the top left corner of the screen, and it would essentially do what the F3 key does; show me all the applications I have open. It doesn't do that anymore. This was my primary way of getting around with applications in full screen, which is why I'm asking about it.

(I was also able to place my cursor in the bottom left corner, and after a few seconds, the screen saver would appear. It doesn't do that anymore either, but that one doesn't bother me as much- was just another thing I noticed that seemed related.)

Is there any way to bring these features back through settings, or do I just have to get used to using F3 now? And if there's no way to get them back, how do I activate the screen savor?

Thank you!