Application Desktop Toolbars

The system supports applications supplying their own desktop toolbars, also referred to as access bars or appbars, that operate similarly to the Windows taskbar. These may be docked to the edges of a screen and provide access to controls, such as buttons, for specific functions.

The system supports the same auto-hide behavior for application desktop toolbars as it does for the taskbar. This allows the desktop toolbar to only be visible when the user moves the pointer to the edge of the screen. The system also provides the "always on top" behavior used by the taskbar. When the user sets this property, the taskbar always appears on top (in the Z order) of any windows and also acts as a boundary for windows set to maximize to the display screen size.

Desktop toolbars can also be undocked and displayed as a palette window or redocked at a different edge of the screen. In the undocked, displayed as a palette window state, the toolbar no longer constrains other windows. However, if it supports the Always on Top property, it remains on top of other application windows.

Note
For more information on the recommended behavior for undocking and redocking toolbars, see Chapter 7, "Menus, Controls, and Toolbars."

Before designing a desktop toolbar, consider whether your application's tasks really require one. Remember that a desktop toolbar will potentially affect the visible area for all applications. Only provide one for frequently used interfaces that can be applied across applications and always design it to be an optional interface, allowing the user to close it or otherwise configure it not to appear. You may also want to consider removing it when a specific application or applications are closed.

When creating your own desktop toolbar, model its behavior on the taskbar. Consider using the system's notification of when the taskbar's auto-hide or Always on Top property changes to apply a desktop toolbar you provide. If this does not fit your design, be certain to provide your own property sheet for setting these attributes for your desktop toolbar. Note that the system only supports auto-hide functionality for one desktop toolbar on each edge of the display. In addition, always provide a pop-up menu to access commands that apply to your desktop toolbar, such as Close, Move, Size, and Properties (but not the commands included on the desktop toolbar).

You can choose to display a desktop toolbar when the user runs a specific application, or by creating a separate application and including a shortcut icon to it in the system's Startup folder. Preferably set the initial size and position of your desktop toolbar so that it does not interfere with other desktop toolbars or the taskbar. However, the system does support multiple desktop toolbars to be docked along the same edge of the display screen. When docking on the same edge as the taskbar, the system places the taskbar on the outermost edge.

Your desktop toolbar can include any type of control. A desktop toolbar can also be a drag and drop target. Follow the recommendations outlined in this guide for supporting appropriate interaction.