Avast sandbox won't turn off.

Earlier today my mother was stuffing around with my computer for whatever reason, only for it to return to me with this ‘Avast sandbox’ around my browser. At first I didn’t mind it until it wouldn’t let me download anything.
I’ve tried just about everything I can to get rid of the darn thing, I’ve turned it off in the avast settings, restarted my computer, I even repaired avast thinking it was a bug.
But nope, still there and it’s bugging me even more than before.

I’ve got a paid version of avast and my operating system is Windows 10. (Yay -_-)

Is there something I’m doing wrong? I’d like to get rid of Avast sandbox as soon as possible please before I start smashing my computer
with a hammer.