An electronic device, while displaying a user interface of an application, detects a user input on a portion of the user interface associated with a plurality of gesture recognizers. A first set of standard gesture recognizers are associated with the portion of the user interface by the application; a second set of supplemental gesture recognizers are associated with the portion of the user interface by a system process; and a first failure requirement determines which gesture recognizers must fail before other gesture recognizers can recognize a user input. In one example, the first failure requirement is that a particular standard gesture recognizer (e.g., an intensity-based gesture recognizer) must fail before a particular supplemental gesture recognizer (e.g., a drag start gesture recognizer) can recognize a user input.