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, wherein the first object represents a first plurality of email messages; and in response to detecting user selection of the first object: toggling display of the first object from a first display state in the electronic message list panel to a second display state in the electronic message list panel, while keeping the first object displayed in-line with the plurality of objects in the electronic message list in the electronic message list panel, wherein the second display state of the first object replaces the first display state of the first object, the first display state of the first object comprises a single summary of contents of the first plurality of email messages, the second display state of the first object comprises a listing of the email messages in the first plurality of email messages, and each email message in the listing is displayed in a third display state comprising a subset of a message body of the email message; 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; detecting user selection of a first email message displayed in the third display state; and in response to detecting user selection of the first email message: toggling display of the first email message from the third display state in the electronic message list panel to a fourth display state in the electronic message list panel, wherein the fourth display state comprises all of the message body of the first email message, while keeping the first email message displayed in-line with the remaining plurality of email messages.