Shadowing via UMS WebApp becomes pretty much unusable for Users with 2 or more monitors. It is super unpractical to display all available monitors side by side.
Even with 2 monitors, its becoming way too small.
Its necessary to have some Switch Focus button, the switch Focus between:
1: All Monitors
2: Just Monitor [1]
3: Just Monitor [2]
4: Just Monitor [3]
…….
Also the Zoom-Feature mentioned in #251 would be great for monitors in different sizes like ultrawide, while the support-team has standard 16:9.

I second this. For users with more than one display, especially if one is an ultrawide and another in portrait, or with 3 or more standard monitors, it becomes impossible to see what is on screen. We are using the classic console as a workaround, but that is not a practical solution.