An electronic device, in response to detecting an input on a touch-sensitive surface: processes the input with a first gesture recognizer for an operating system application; and processes the input with a second gesture recognizer for a first software application, distinct from the operating system application. If the first gesture recognizer recognizes the input as a gesture matching a gesture definition of the first gesture recognizer, the device performs an operation defined by the operating system application and transitions the second gesture recognizer into an event impossible state. If the second gesture recognizer recognizes the input as a gesture matching a gesture definition of the second gesture recognizer, the device delays performance of an operation defined by the first software application for the input until the first gesture recognizer indicates that the input does not match the gesture definition of the first gesture recognizer.