I'm not sure i understand your question exactly, but when i start it shows me the left and middle monitors, when press the right arrow it will shift and show me the middle and right monitor. Is that what you mean?
Sorry, I meant if you drag the viewer across to the 3rd monitor yourself.
What operating systems are in use at both locations?
Are the 3 monitors at both locations arranged in identical fashion?
Do they all have matching resolutions?
I have not tried manually dragging it, i will try tonight.
Operating systems are the same - windows 10. I adjusted the resolution so they match (that's how i was able to go from 1 to 2 monitors) and monitors are arranged in identical fashion.