In state 50-2, some or all of the functions of devices 10A and 10B may continue to operate independently. For example, devices 10A and 10B may display separate content on their respective displays (e.g. a first web page on device 10A and a second web page on device 10B) and/or may play separate audio. At the same time, the joint operating mode may allow at least some of the functions of devices 10A and 10B to be shared. As an example, a wireless communications circuit in device 10A may transmit and receive data for both device 10A and device 10B (and this data may be exchanged locally between devices 10A and 10B using a wired or wireless link between devices 10A and 10B) or measurements from an ambient light sensor in device 10A may be used in controlling screen brightness in the displays of both devices 10A and 10B.

If desired, devices 10A and 10B may operate in a coordinated fashion during the joint mode of state 50-2 so that most or all functions of the devices are coordinated. For example, images that are displayed may be expanded to stretch across displays 14A and 14B to provide a user with an expanded display area, stereo audio may be played from a first speaker in device 10A and a second speaker in device 10B, touch input may be gathered from displays 14A and 14B so that a user can drag on-screen items from display 14A to display 14B or can make touch gestures that extend across displays 14A and 14B, wireless communications capabilities of devices 10A and 10B may be combined to provide enhanced bandwidth and/or additional bands of coverage, etc.