The four contexts are exposed in the horizontal navigation menu across the top of each page. The contexts progress from left to right in the order they are listed above. Each change of context triggers changes in the fundamental components of the interface. These components include the navigation sub menus, the blockset and the action icons.
When creating a custom user interface component, such as a page, block or dialog, it is important to specify the context it can appear in by listing the contexts in the
@scope attribute of the layout configuration.