1. A method of operating a user-interface using mid-air motion of a human target, comprising: receiving a plurality of images from a capture device, the plurality of images including the human target; tracking movement of the human target from the plurality of images using skeletal mapping of the human target; determining from the skeletal mapping whether the movement of the human target satisfies one or more filters for a first mid-air gesture; determining whether a modifier for the first mid-air gesture is present; if the movement of the human target satisfies the one or more filters and the modifier is not present, performing a first user-interface action corresponding to the mid-air gesture; and if the movement of the human target satisfies the one or more filters and the modifier is present, performing a second user-interface action corresponding to the mid-air gesture.