Thanks for these suggested intermediate remedies. My question remains unresolved. This problem thus seems somewhat complicated, so please allow for my further elaboration as follows:
Can someone please tell me how to run Roon with scalefactor=2? Or how to change windows scaling to 200%. I haven’t got a clue, and is it at all possible unless the application itself offers a scaling feature? I haven’t seen that.
Importantly, I would like to repeat that running in scale factor 1.5 (see above in this thread) did not remedy this problem.
Moving the Windows taskbar to one of the sides so as to allow for “720” was not effective.
There is a “brute force” feature to disable any Windows scaling, i.e. the “disable display scaling on high DPIs” under application properties, thus forcing Roon to run in 3200x1800 resolution. This does not solve the problem, but it can be noted that it has the consquence of moving the position of the startup quote from an “upper left” to a center position on the screen, i.e. there is a change in behaviour. I anticipate this is just a sign of most of the Roon GUI (except the quote and the misinterpretation of screen resolution) already being brought in compliance with the high DPI scaling machines?
To be strictly correct here, I am actually running not 1280x720, but actually 3200x1800, but when Windows scales (like a digital zoom) certain applications not yet tuned for higher dpi scaling, then this results in a 1280x720 quality, which is indeed a lousy and blurred quality on this computer. Hence, this is at best an intermediate remedy.
Important: Roon takes full advantage of the “native” 3200x1800 display resolution. It means the only problem with Roon at present is the incapacity for running in windowed mode on this computer.
Software applications are more and more emerging that are properly tuned to take advantage of the high dpi scaling. Examples are Microsoft Edge (even if it says it scales to 250% it has full granulation according to the computers display resolution) and Chrome.
For all the non-compliant apps, one remedy is to scale down the computer to 1920x1080, which is a “standard” quality as of 2016. This does not help for this Roon problem.
I have 3 days left of my trial, but the rest of Roon is excellent to the degree that this is not a showstopper.
For anyone with the same problem: My remedy is that I have learned to switch between “full screens”, like Roon, the desktop, etc. (Window button + tab).