Show Window Contents or Outline While Dragging

This is sooo randomic!

Here's what happened:
I followed those two tutorials. It didn't work, the problem was stil there.
So I said myself "let's try to set the other account as a local one and see what happens!"
So I log in that other account (which is still another Microsoft Account) and the problem appeared there before I could do a thing!
I didn't modify anything, and it appeared...
So I did immediatly log out and re-log in on my usual account, and now the problem doesn't show...
It makes no sense to me!
What should I do? Hope that it won't show anymore?

Thank you for your patience anyway!

EDIT:
Uhm so, I plugged in an external HD and it did it again, I had to go to performance settings, it was set on "Custom" and I had to set it again on "Adjust for Best Appearence". I tried to simulate it again (unplugged the HD, replugged it in) but this time it did not trigger the glitch.
I don't know if this can help... (I didn't log out/restart my laptop this time) !

I just want to say thanks for this great tutorial; I have referred to it on a number of occasions.
Here is my most recent episode(s) with the situation:

"Show Window Contents while Dragging" somehow got turned off ???

I will add this: in my Control Panel, instead of "Performance Options", it says "Performance Information and Tools"; I clicked that and there was "Adjust Visual Effects" at the top of the left pane.

Thanks again.