Taskbar

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In computing, the taskbar is a term for an application desktop bar which is used to launch and monitor applications. The taskbar concept was first implemented in Acorn Computers' Arthur operating system, which was released in 1987 for their Acorn Archimedes computer. Microsoft incorporated a taskbar in Windows 95 and has been a defining aspect of Microsoft Windows's graphical user interface ever since. Other desktop environments, such as KDE and GNOME also include a taskbar.

[edit] Microsoft Windows

In Windows, the default location for the taskbar is at the bottom of the screen, and from left to right it contains by default the Start menu button, Quick Launch bar, taskbar buttons and notification area. With the release of Windows XP, Microsoft changed the behavior of the taskbar to take advantage of Fitts' law.^[1]

[edit] Taskbar Elements

The Start menu button contains commands that can access programs, documents, and settings.
The Quick Launch bar, introduced with Internet Explorer 4, contains shortcuts to applications. Windows provides default entries, such as Internet Explorer, and the user or third-party software may add any further shortcuts that they choose. A single click on the application's icon in this area launches the application. This section may not always be present: for example it is turned off by default in Windows XP Home Edition,^[2] although it can be enabled.
The Windows shell places a taskbar button on the taskbar whenever an application creates an unowned window: that is, a window that doesn't have a parent and that is created according to normal Windows user interface guidelines. Typically all Single Document Interface applications have a single taskbar button for each open window, although modal windows may also appear there.
- Windows XP introduced taskbar grouping, which can group the taskbar buttons of several windows from the same application into a single button. This button pops up a menu listing all the grouped windows when clicked. This keeps the taskbar from being overcrowded when many windows are open at once.
- Windows Vista introduced window previews which show thumbnail views of the application in real-time. This capability is provided by the Desktop Window Manager.
Deskbands are minimized functional, long-running programs, such as Windows Media Player. Programs that minimize to deskbands aren't displayed in the taskbar.^[3]
The notification area is the portion of the taskbar that displays icons for system and program features that have no presence on the desktop as well as the time and the volume icon. It is commonly referred to as the system tray, a name Microsoft considers incorrect^[4]. It contains mainly icons that convey status information, though some programs, such as Winamp, use it for minimized windows. By default, this is located in the bottom-right of the primary monitor (or bottom-left on languages of Windows that use right-to-left reading order), or at the bottom of the taskbar if docked vertically. The clock appears here, and applications can put icons in the notification area to indicate the status of an operation or to notify the user about an event. For example, an application might put a printer icon in the status area to show that a print job is under way, or a display driver application may provide quick access to various screen resolutions.
- Starting with Windows XP, the user can choose to always show or hide some icons, or hide them if inactive for some time. A button allows the user to reveal all the icons.
- Starting with Windows Vista, the taskbar notification area is split into two areas; one reserved for system icons including clock, volume, network and power. The other is for applications.

[edit] Customization

The Windows taskbar can be modified by users in several ways. The position of the taskbar can be changed to appear on any edge of the primary display. Up to and including Windows Server 2008, the taskbar is constrained to single display, although third-party utilities such as UltraMon allow it to span multiple displays. When the taskbar is displayed vertically on versions of Windows prior to Windows Vista, the Start menu button does not display the text "Start" or translated equivalent.^[5]

Users can resize the height (or width when displayed vertically) of the taskbar up to half of the display area. To avoid inadverdent resizing or repositioning of the taskbar, Windows XP Home Edition locks the taskbar by default.^[2]^[6] When unlocked, "grips" are displayed next to the movable elements which allow grabbing with the mouse to move and size. These grips slightly decrease amount of available space in the taskbar.

The taskbar as a whole can be hidden until it the mouse pointer is moved to the display edge, or has keyboard focus.