1. A method of navigating between application contexts in a portable device, comprising: displaying a current application context of a messaging application in an application display region of a display, wherein the current application context is a current mailbox context; displaying a navigation bar adjacent to the application display region, the navigation bar including at least three horizontally adjacent regions, comprising a current context region for displaying an indicator of a second application context comprising the current application context, a prior context region for displaying an indicator of a first application context comprising an application context preceding the second application context, and a link region, wherein the current context region, the prior context region, and the link region each maintain a fixed location on the display in the navigation bar; upon detecting user selection of the prior context region, shifting operation of the portable device to the first application context, including displaying in the prior context region of the navigation bar an indicator of a fourth application context comprising an application context of the messaging application that preceded the first application context; and upon detecting user selection of the link region, changing a message displayed in the current mailbox context.