How to use any app in assigned access mode in Windows 10
As I wrote before, by default when you setup assigned access the UI only shows app which have the aboveLockScreen extension registered. I talked to the PM who owns this feature to ask why and the reason is because we changed the behavior of how assigned access works (lock the screen and launch the app above the lock screen) we found out a lot of existing apps crash when running on the lock screen, so we changed the UI to only show apps which are designed to run above the lock screen.