1. A method of a computing system that has a surface, the method comprising: detecting a first set of one or more contacts, each contact corresponding to a hand part touching a touch sensor surface of the computing system, the touch sensor surface being a portion of the surface of the computing system on which the computing system detects contacts, wherein commands of the computing system are selected based on detected contacts; selecting a first command based on the first set; detecting a touch down of each contact of a second set of one or more contacts on the touch sensor surface while the first set remains touching the touch sensor surface, each contact of the second set corresponding to a hand part touching the touch sensor surface; and ignoring the second set by maintaining the first command after the touch down of the second set and by not selecting a command of the computing system based on the second set.