The problem of high DPI briefly explained:
According to this site:
The problem in Windows 10:
When you have a widescreen, with a
resolution of 1920x1080 or higher or a bit lower, in Windows Vista, 7,
8 and 8.1 you would put your DPI scaling to 125% or higher to make
text and images appear larger and more easy to read. But when you put
the DPI scaling to 125% in Windows 10, you see in a lot of dialogs and
windows the font gets very blurry.
And then it continues:
At some point we can understand Windows why they changed the DPI
scaling in Windows 10. It is probably ment to support mobile devices
more easy. But if you like to use your Desktop as a Desktop, and you
demand high quality only. Then you can use this fix until Microsoft
has addressed this issue.
So, if you use your Windows 10 only for a Desktop purpose, you can download their free program called XPExplorer from here.
Why use this program and not some registry change?
The site answers:
Why this is a small software program, and not some 'Registry Tweak' is
because when you manually adjust the DPI settings at your 'Windows
Registry'. Windows will reset your dpi settings every 2 reboots. Which
means you would have to adjust the registry again (Microsoft forces
you almost to use its new DPI scaling method).**
I can confirm this solution works well (as well after reboots) on my Windows 10 setup.
Windows Picture and Fax Viewerwhich was part of Windows XP.