Taskbar

The taskbar is a user interface element used in Microsoft Windows and other operating systems that allows users to quickly switch between different tasks and windows, as well as allows easy access to core system functionality. In Windows, the taskbar also includes the Start button for accessing the Start menu and the notification area with a clock, which can be used by applications to report their status.

History
Prior to the introduction of the taskbar in Windows 95, minimized windows were represented by icons on the desktop. In Windows 1.0, all windows were visible at all times. Unless a single window was maximized (zoomed), all open windows tiled the screen, while minimized (iconified) windows were shown as icons in the lower part of the screen. The introduction of overlapping windows in Windows 2.0 meant that windows, including minimized window icons could now be covered by any other window, which was later found to result in many users ending up losing track of their open applications.

At first, the Cairo project tried to fix this problem by adjusting the appearance of minimized windows, as the developers believed that users had trouble distinguishing minimized window icons from other kinds of icons. The team came up with wide plates with the window icon and title. The new user interface proposed by the project also included a so-called system tray, which could be either docked to any side of the screen or floating as a window. The tray included three buttons named System, Find and Help on one side, which provided simple access to basic system features, and a clock on the other side. The main part between the clock and the system buttons was occupied by a folder view, which functioned as a clipboard.

The Cairo user interface was later adopted by the Chicago project and included in early builds, such as build 58s. The team also worked parallelly on a separate user interface concept called ClearView with the aim to create an alternate shell for beginner users. ClearView used a full screen tabbed interface for launching programs, accessing recently opened documents as well as switching between windows. The tab bar on the top of the screen ultimately became the modern taskbar, with a Start button and buttons representing each window. ClearView was eventually morphed with other parts of the Cairo user interface to become the modern Windows shell.

Windows Desktop Update
The taskbar was further refined during the development of during Windows 98 and Windows 2000 and the accompanying Windows Desktop Update. The ability to use custom toolbars was added, which could be added to the taskbar but could also be docked on different sides of the desktop. Third party applications could also install their own toolbars. Built-in toolbars included a folder toolbar showing the items of a specified folder, which was used for the Quick Launch Bar, as well as the Address and Language Bar toolbars. The taskbar could now also be resized by dragging its outer edge.

For two brief periods, a Show Desktop button was also added to the right corner, behind the clock. It was later removed in favor of a shortcut in the Quick Launch Bar, however, the feature remained in Windows CE and was later reintroduced in Windows 7.

Windows XP introduced more small improvements to the taskbar, however, the fundamentals remained the same. The taskbar could now be skinned with the introduction of visual styles and taskbar buttons could now also be grouped by applications when the taskbar was full.

Longhorn
Similar to other parts of the shell, the taskbar was also affected by the user interface work during the Longhorn project. As early as build 3706, it was rewritten using the Avalon framework and tightly integrated with the new sidebar. The integration allowed parts of the taskbar such as the clock, notification area and the Quick Launch Bar to be moved to the sidebar, freeing up space for the taskbar buttons. At one point, the taskbar and sidebar could be combined into a single large bar docked to a side of the screen.

After the development reset, the team reverted to the original Windows XP taskbar with minor improvements. The Start button was changed to the Windows orb, which was taller than the rest of the taskbar. Furthermore, when the Windows Aero theme was enabled, the taskbar was translucent and hovering over taskbar buttons showed window previews.