Incorrect font size in some windows apps

Since a day ago, without me doing anything(!), some parts of apps are shown in a different font size and some windows are shown bigger that it was before when they were normal, and I don't know how to fix it. Have a look at the images attached. When I used snipping tool to take screenshots I noticed that there a large white space surrounding the capture, as much as I can remember it was not there when I took screenshots before. What's wrong with Windows?

It depends on the person who created those metro apps. As for software, same thing.