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 the first region and extends to the second region. The device sends a touch began event to the first software application in response to detecting the first touch input at a first location corresponding to the first region, sends a touch cancel event to the first software application in response to detecting that the first touch input has left the first region of the user interface, and sends to the second software application information corresponding indicating that the first touch input has entered the second region of the user interface in response to detecting that the first touch input has entered the second region of the user interface.