Blade 2016 connect multiple displays

Hi folks,
I want to use my 14" Razer Blade with two external (touch)screens: one via Thunderbolt the other one via HDMI.
Connecting only one display at a time everything works fine. Adding the second one only the HDMI (connected screen gets a signal and the touchfunction of the TB-one is assigned to the the HDMI-screen as well.

I know the CPU can handle three displays in total.
I tried several drivers for intel & nvidia GPU.

Any advise? It seems that the thunderbolt only serves as a USB-connection as soon as the HDMI is connected. Is there a hidden checkbox to use both output simultaneously? Is it an HDCP-issue?

thanks in advance