DPI scaling behavior in Windows 8.1?

When using DPI scaling in Windows 8.1, I've noticed that different programs are scaled in different ways:

1. Scaling fully supported: This results in the best experience by far, but it seems only a handful of Windows components (e.g. Windows Explorer and Control Panel) as well as Office 2013 have this...
2. Magnification: Everything is blurry (much like zooming in on a JPEG), but aspect ratio is maintained. Virtually all Windows components that don't have full support for scaling use this mode, for example Event Viewer and Task Scheduler.
3. Text is enlarged, but spacing and icons are not: This scaling mode leads to all sorts of clipping and overflow issues. Unfortunately, most 3rd party programs use this method

My question is, how does Windows decide how to scale any given program? And is there any way for end users to change it? I'd love to be able to avoid scaling method #3...