Cjdshaw, thank you for your advice.
HURRA, It Works....
I got it, it works!
1) I installed the latest Nvidia drivers supporting Nview 3.0. This allows to set a proper Dual view mode with independently working monitors. It was the first time that MC10 displayed a display #1 and display #2 option in Configure Display.
2) I then started a slide show on zone 1 on display #1. If I go full screen the window gets black and full screen is displayed on the second monitor.
3) I then started a slide show on zone 2 and set inside configure Display: display #2. Then went full screen. Slide show started in zone 2 was shown on second monitor.
4) Switching back to zone 1, setting display #1 again and going full screen displayed this slide show on the first monitor. So I had two independent slide shows going on. That's simply a great feature.
5) Definitely the handling needs some improvement. It's rather complex to set up and keep going. I imagine that we should be able to associate a particular monitor with a particular zone, so that when I start a slide show or a combined music/image playlist it goes directly to the specified zone.
I think this has real potential. You could have different zones, each with its own display, visualizations, slide shows etc.. This is a big winner.