Windows 10: Run app 'full screen' in part of 4K screen

Hi All,
Sorry, I'm not quite sure where this question fits, but hopefully someone will find it.*Smile

I've recently upgraded to a 4K monitor instead of running 4 separate 1080p screens which is working very well except for the fact that I can't run 'full screen' without the app running on the whole monitor (obviously...). So my question is whether it is possible, either directly through Windows or a 3rd party app, to partition/frame the single screen into parts that will allow an app to run in full-screen mode within the frame?
Thx
Gav

:)

 

How to stop windows 10 windows moving after full screen app exits

I run 6 window's 10 desktops on my Nvidia 1070 connected to 2 4K screens in horizontal span mode. The task bar is set to extend across the bottom of both screens.

When I exit from an app that runs in full screen mode started on any desktop, the windows on desktop 1 rearrange to the resolution of the full screen app. On all the other desktops the windows are as they were before the full screen app ran.

How do I stop the desktop 1 windows from rearranging?

 

How to COMPLETELY disable windows automatically resizing & snaping: W10, W7

So what's really works for Windows 10?

I've tried the slower mouse double click -- that doesn't work. Any slight movement via the title bar and BOOM, full screen on my 4K monitor (3840 x 2160) blocking many screens.

All of the Snap Multitasking settings are set to Off. Moving the title bar in a window a little, and BOOM full screen on my 4K monitor.

This does not work:

How to disable the snap feature on Windows 10 - Windows 10

WindowArrangementActive to 0

THIS MAXIMIZING TO FULL SCREEN IS MORE THAN QUITE ANNOYING. I don't want ANYTHING going full screen on my 4K monitor.