I have a high-dpi laptop and while at work I connect this to 2 external monitors which I work on (non-high-dpi) - then at home I work on the laptop monitor.
Scaling is broken is so many ways it will be hard to list them all, I was waiting for the anniversary update to reach me but all this did when it installed was undo the workaround registry entry I had in place which made my problems worse instead of better - no change to the underlying problems though.
Some applications scale beautifully but 99% do not. The fact is that with a hack of adding the "Prefer external manifest file" registry entry and manually creating manifest files I can get most apps to then scale correctly - why can't windows figure this out if I can.
The problem is worse because I just put my laptop to sleep at work and then when I open it at home I need to then close each application, disable the high-dpi scaling and re-open them to work decently again. The applications included in this list that do not work are Office 2016, windows explorer and all my other tools but I thought I would mention the MS ones as surely you would have worked on getting these going first.
All webbrowsers dont scale which makes for a terrible experience on the external displays, copying and pasting is ridiculous because it doesn't try and be smart about it and it required quite a bit of testing to make sure I send what I meant to and not an insanely small or large copy.
With the proliferation of high-dpi laptops and a hectic mix of hardware people might use I would have thought this would be a priority (3 years ago) but it seems I am being punished for spending the extra money on a fancier machine.