Application change sets sound to mute

I'm using a second, smaller screen as an EFB for charts, to look at my flight plan and to do my takeoff calculations in TOPCAT while in the sim. However, the P3D sound stops whenever I click on something in the smaller screen which, I know, is obvious since I'm switching applications. I just find this a bit annoying and am wondering if there's a way to keep the sound on when making selections on the smaller screen.