Devices and methods for processing touch inputs over multiple regions of a touch-sensitive surface

An electronic device, while displaying a user interface that includes a first region corresponding to a first software application and a second region corresponding to a second software application, receives a first touch input, on a touch-sensitive display, that originates from a first location corresponding to the first region and extends to a second location corresponding to the second region. The first region includes a non-boundary region and a boundary region. In response to receiving the first touch input, when the first location corresponds to a non-boundary region of the first region, the device processes the first touch input with the first software application. When the first location corresponds to a boundary region of the first region, the device conditionally processes the first touch input with the second software application.