Trying to run Forza in the background without pausing

I built a mini race simulator for my son to play Forza on another monitor connected to my computer. I want to be able to use my computer at the same time but when I click off of Forza on my other monitor it pauses the game. Is there any way to keep forza running in the background so it will not pause when I click off of it?

Here is a photo of my setup as well so you can get an idea what I am trying to do.

racing setup