After some uninstall/re-install/patch action I finally got a decent working install on Windows 10 (Pro). The main trick is the DDFIX 1.15.13 Mod.
I can now task switch and have no screen corruption while flying.
everything runs very fast and smooth.
I can tune a lot of the visuals with nVidia Control Panel
Task switching while in menu will result in a black screen, but mousing over will reveal click spots.
I cannot get it to run in a higher resolution than 1024x768 (always get a complaint of "ERROR: GetFlyScreenMode:can't find any supported screen mode" when I try to set a higher res in cam.cfg)
There can be screen flicker in aircraft panel areas and the mouse will create trails on certain gauges, both clear up with some view switching.
Compatibility Mode doesn't seem to affect anything more than sound; without it the engine and effects seem to cut in and out. But my current setting of Windows XP sp3 seems to resolve all of that.
When I get time I will try the Panel fix I've seen posted elsewhere to see if that clears up the flickering and mouse trails.
I would very much like to be able to use native screen res of 1920x1080, but nothing I have tried has resulted in anything better than black/gray screens (FUMode=1 in ddfix.ini).
Hope someone can help get us the rest of the way there.