1. A method of managing a display device of a portable communication unit, comprising: executing a first application on the portable communication unit; assigning a first display area of the display device to the first application for outputting first graphic output content; executing a second application on the portable communication unit; assigning a second display area of the display device to the second application for outputting second graphic output content with the relevant display areas being assigned so that they do not overlap; assigning a priority to the first application and the second application with a size of the relevant display areas being determined depending on the assigned priority; assigning a higher priority to system applications than non-system applications, the system applications to provide system related messages; and assigning a larger display area to the application having the higher priority, the larger display area to display the system related messages when the application is a system application.