Hah..this subject only for Mac users...

Ever wish you could view one window while working in another window? (imagine that you want to watch the dvd tutorials and followed every step at the same time) If you are a Pc ,then that is not a problem! but how do you do that on the Mac...

[Afloat] is your solution.Afloat also allows you to set a window to 「always on top」
and Afloat is donationware , click here to the webside and download it now!