1. A method comprising: at a computing device having one or more processors, a display and memory storing one or more programs for execution by the one or more processors: displaying a user interface for a messaging application, the user interface comprising an electronic message list in an electronic message list panel having a boundary, wherein the electronic message list comprises a plurality of objects and each respective object in the plurality of objects (i) is visually distinct in the electronic message list and (ii) represents one or more corresponding electronic messages in a plurality of electronic messages; detecting user selection of a first object of the plurality of objects in the electronic message list panel; and in response to detecting user selection of the first object: toggling display of the first object from a first display state to a second display state, wherein the second display state of the first object replaces the first display state of the first object; moving a first subset of objects in the plurality of objects vertically upward, wherein the first subset of objects comprises one or more objects above the first object in the electronic message list panel and wherein the moving the first subset causes all or a portion of at least one object in the first subset of objects to move outside the boundary of the electronic message list panel and to no longer be displayed; and moving a second subset of objects in the plurality of objects vertically downward, wherein the second subset of objects comprises one or more objects below the first object in the electronic message list panel and wherein the moving the second subset causes all or a portion of at least one object in the second subset of objects to move outside the boundary of the electronic message list panel and to no longer be displayed.