Read about Photoshops various screen modes and you might learn a thing or two.
1. Pressing the 'F' key allows you to scroll through the different screen modes. The first mode is Standard Screen mode which is the default.
2. Next comes Full Screen mode with Menu Bar. In this mode, the background becomes gray; if you would like to change this, select what color you would like the background to be as your foreground color, select the paint bucket and while holding Shift, click on the gray. The gray becomes your foreground color. Very useful.
3.
The last screen mode is Full Screen Mode. You'll notice that you don't have
a Menu Bar. But if you're a Window's user, you'll notice an arrow on your Toolbox.
Click on it, and would you look at that? You actually do have a menu bar (if
you're using Windows). This feature isn't available on the Mac. Windows users
rejoice :). The Full Screen Mode is very useful when you're on very large
images. Also, if you have most of the shortcuts in Photoshop memorized, hit
the Tab key and all the palette and the Toolbox disappear, giving you a
clutter free work environment.
More Photoshop: 
