I need help with Hdmi mirroring with TouchUI

Hello,

I have a pi3 B that was able to boot to desktop and output to an adafruit 3.5 tft and my HDMI monitor.
In the desktop, using a browser, I was able to launch Octopi/TouchUI,
I wanted TouchUI to auto-load and I cloned the proper repository, ran the helper and now it auto loads. The problem is now the HDMI monitor is only displaying a black screen after the initial boot and splash screen. The tft display works fine.

Is there a setting or software I can install to get the mirroring working again ?
Or is there a different way to auto-load that will no break mirroring ?

Regards,
David.