1. A non-transitory computer-readable medium having stored therein instructions executable by one or more processors to cause a control device to perform operations comprising: displaying, on a user interface, a zone identifier that identifies a zone of a media playback system, wherein the zone comprises one or more playback devices, wherein at least one of the one or more playback devices has audio-playback software installed thereon; sending, by the control device to a given playback device of the zone, a command that causes the audio playback software to initiate playback of media in the zone; receiving, via a network interface from the given playback device, status information indicating that a particular add-on software component is assigned to the zone, wherein the particular add-on software component modifies playback of media in the zone; and displaying, on the user interface of the control device, an application identifier in association with the zone identifier, wherein the application identifier indicates that the particular add-on software component is assigned to the zone.