I'm Surprised and confused about
It is officially stated somewhere (where?) you do NOT support, or you do not "officially support"?
Or are you only talking about different DPI monitors?
So many of your ambassadors like Donley etc. say multi-monitors ara a must, and also, the use of palette windows vs. docked palettes make more or less only sense on multiple monitors i think...
How does that fit with the 2017 announcement
High DPI Modeling
We’ve tuned snapping and inferencing for high definition monitors (like Apple’s Retina Display). Edge weights have also been smart-scaled. You can back away from your screen now...
Is that Modeling marketing speak for ONLY Modening, but not UI? No general HiDPI compatibility, just the modeling area?
Well, like that, i can't back away from my screen as i'd like to.
Back to the issue, i have to admit i mixed SU and LO in the post above, and now i am not sure if you did too.
Is Trimble officially supporting the same system specs for both, or does it differ?
They behave different, neither bug-free. Aparently, they have a very different code-base with a different UI framework? LO seems to work less nicely with windows than SU. LO only shows frames of moving windows, which are still heavily flickering, while SU cleanly shows moving windows with content.
The Scaling is taken from the Screen on which SU starts.
On the 4k 250% screen there's no scaling as you said.
On the 100% 125% screens it scales correctly, but only after a window is moved, so my saved setup is never correct upon re-opening SU (tray windows all set to the same width on the same screen):
It's always taking the DPI from the system-primary screen, regardless on which it started. (Splash is always on primary)
Also, it reads the DPI in a way, so only after a reboot it gets the new value, changing display settings is not enough.
Moving trays on a screen with different DPI, the tray-window moves at different speed than the mouse.
This makes LO only work correctly on the system-primary screen... Is that covered with the official non-support for systems with multiple monitors, or is it a bug
As for the Answer 2), this is a workaround for the 4k display, half the resolution still looks good. But on the 100% 125% screens, which are the big ones i use, it's not really an option.