Surface Pro 4 as magnifying glass , showing a magnified portion of a bigger 2:nd monitor?

[Kjell Blomqvist]

Does anyone know of an application that can do this?

I write music i.e. populating staves with notes and music symbols. I have a 21,5" screen in portrait mode with most staves of an symphonic orchestra visible. I whish to use the Surface as a magnifying glass to do the editing on, and at the same time have the overall visual control over the complete orchestra, on the big monitor... I run the music editing software on the Surface.

Is there any way to achieve this?

[#2]

Try opening Microsoft Office Lens on the screen on which you want to do editing.  You should be able to use multi-touch to expand the image that is displayed.