The Language Viewer is a tool which is provided to help the user identify the current state of the language support, by providing visual indications that represent the current bidirectional state of the window that has the focus.
The default Viewer is implemented as a PM/WorkplaceShell application that shows a number of icons that represents the current bidirectional attributes as well as the active keyboard layer of the window that has the PM focus.
The Viewer is optional. The PM bidirectional support works even if the viewer application is not active. In addition, the viewer can be replaced by a user-written application. Such an application can modify the visual effect that is provided to the user, allowing for more flexibility of the user-interface.