A portable electronic device with a touch-sensitive display is disclosed. One aspect of the invention involves a computer-implemented method in which the portable electronic device: displays an application on the touch-sensitive display; and when the application is in a predefined mode, performs a predefined operation in response to each gesture of a set of multiple distinct gestures on the touch-sensitive display. Another aspect of the invention involves a computer-implemented method in which the portable electronic device: displays a first application; when the first application is in a first mode, performs a first operation upon detecting a first gesture on the touch-sensitive display; and performs the first operation upon detecting a second gesture on the touch-sensitive display, wherein the second gesture is different from the first gesture.