So i had this problem before, and with the help of these forums, i got it worked out. However now i've replaced a monitor with a new one, and nothing seems to work.

I would like an App from the Microsoft Store (called MobileSheets) to launch when my monitor profile changes from 2 to 3 monitors. I've followed the instructions previously given, and they dont seem to work.

I have attached a debug file if it is helpful.

Thanks in advance!

It doesn't launch at all. I havent put in the trigger to move it yet. I was just going to get it launching, before i worry about which screen it goes to.

Ok, i've solved the problem. It turns out that when you replace a monitor, you need to update your monitor profiles. With the new monitor, DispayFusion didn't detect the '3 Monitor' profile, becuase i guess it was a slightly different '3 monitor' profile with the new monitor. If that makes sense.
Thanks