The window is the basis for the graphical user interface. Xerox developed the first graphical windowing user interface. This style of interface was first popularized by Apple and later by Microsoft, butXerox developed the first graphical windowing operating system more than a decade before the first Mac or Windows computer ever saw daylight.
Most windows are rectangular, but irregular shapes are allowed too. (See Windows Media Player in Chapter 4 for an example.) Standard windows have a titlebar across the top, which, in addition to identifying the window and the currently open document (if applicable), is used as a handle with which to move the window around the screen (see Figure 3-36). The titlebar also shows which window is currently active; depending on your color settings (set through Control Panel → Display → Appearance tab → Advanced), the titlebar of active window will typically appear darker than the others. (Small floating toolbars in some applications ignore this rule, always appearing either inactive or active.)
Figure 3-36. A garden-variety window, complete with title, menu, and client area
The elements commonly found on window titlebars are described below (any or all might be missing, depending on the type of window).
Click the icon on the upper-left corner of a window or press Alt-Spacebar to display the control menu, which duplicates ...