1. A user interface apparatus, comprising: a display unit comprising an object display area, the display unit displaying an object in the object display area; a detection area control unit that: defines a detection area for the object, the detection area including the object display area and having a size and a location; and changes at least one of the size and the location of the detection area to create a modified detection area; and an activation detection unit that detects a position of a user activation; wherein the detection area control unit changes the detection area after the activation detection unit detects the activation position as being within the detection area.