Optimus - multiple displays - which graphics?

I am running two very graphics and CPU intensive programs simultaneously on two displays, the laptop display and an external monitor connected by HDMI. (x-plane and simavio). At least one of them runs on the OpenGL API, not directX.

Both are set in Nvidia control panel to run on the GTX.

Are they both running on the GTX, even though output is on two monitors? The multiple display setup shows the laptop panel running on the Intel graphics, and the external monitor running on GTX. On the other hand, the performance of the applications implies they are both running on the GTX.

1) Are they both running on the GTX?
2) Is there any way to really monitor or see what is happening on the graphics chips?
3) Is this a unique situation because of OpenGL being used?

Except for the fan noise, it appears to work quite well, but it is fiddly to set up each time (moving windows to the right display, sizing, ...)

 

Yes, I found the "monitor" from the Nvidia control panel system tray icon, but it doesn't appear to reflect reality. Looking at frame rates I can tell what is running where. Any other/better tools?