a graphical user interface allows users to access multiple third party services and enables the services to provide functionality within the gui adjacent to core functionality of a host application . the gui provides an interface region for third party service functionality that is distinct from , but equal in exposure and prominence to , the core functionality provided by the application hosting the gui . the gui enables seamless switching between a list of available services provided in a service menu . switching between services replaces service function buttons and service branding according to particular service customizations .