The active window

When you have two or more windows open on the desktop, only one window is the active window. If
you use the keyboard at all, it’s important to know which of those windows is currently the active
window, because that’s the only window that can accept keyboard input. If I were to try to type text into
the WordPad document shown in Figure 2-6 right now, no text would appear in the window. Why?
Because currently the Calculator program is in the active window, and only the program in the active
window will respond to input from the keyboard. The problem is easily solved. Just click anywhere on
WordPad’s window to make it the active window, and start typing.
If you look at the taskbar in Figure 2-6, you’ll notice that it now contains four new buttons labeled
WordPad Doc, Solitaire, Calculator, and My Computer (which actually represents the Windows Explorer
program, as discussed later). The taskbar always displays a button for each “running task” — that is,
each open program on the desktop. You can usually tell, at a glance, which window on the desktop is
currently the active window by the following clues:
The taskbar button for the active window is colored a little differently, and appears “pushed
in.”
The title bar for the active window is a little brighter than the title bars of the inactive
windows.
The active window is always at the “top of the stack.” That is, no other windows overlap the
active window.