You can add multiple desktops to the Mac OS X Mountain Lion by using Mission Control, formerly known as Spaces. Can be really useful if you are a busy multi-tasker.
The blurry, transparent background in Notification Center, Control Center, Spotlight and other more options menus on iOS 7 device can make reading experience rather unpleasant.
Knowing how to select parts of your Gimp documents with the help of Quick Mask might be one of the first things you should learn when starting with Gimp. Let me introduce you to the basics of Quick Mask.