I have X1 configured to start when windows starts and be minimized and also minimize to the Notification Area on application close.
When I start Windows, X1 is indeed in the notification area minimized. However, once I open it and then exit from it, the icon is NOT visible in the Notification Area either in the visible part or in the hidden overflow notification area. It simply is not there. I have to find the program in the Start Menu and restart it.
So "minimize to the Notification Area on application close" is not working.
I have fully up to date Windows 10 and X1 8.5.2 6001si (64-bit) on a trial basis.