I was tweaking my new Mac (I'm new to OS X) and suddenly I noticed that the icons in lots of my apps changed. I've checked all the things I done (using OnyX) but can't find what I done to make my apps look like this:

The solution is probably on the web somewhere but I can't find it - I only find issues related to icons of apps and folders.
All tweaks were done through OnyX. I ran maintenance scripts, cleaning, and changed some parameters settings (iTunes settings, Login background).