1. An apparatus comprising: a processor and memory running an application using one or more gestures as inputs; a touch-sensitive display for sensing two-dimensional gestures in a two-dimensional plane; a first non-contact three-dimensional gesture sensor for sensing a user's hand movement in front of and relative to the touch-sensitive display; at least a second non-contact three-dimensional gesture sensor for sensing the user's hand movement in front of and relative to the touch-sensitive display, the first and second non-contact three-dimensional gesture sensors employing differing gesture-sensing modalities; a control circuit operably coupled to the first and second non-contact three-dimensional gesture sensors and configured to switch between the first non-contact three-dimensional gesture sensor and the at least a second non-contact three-dimensional gesture sensor while in the process of detecting a current three-dimensional gesture of the user's hand movement, wherein the switch is based on each of remaining predictable portions of the currently detected three-dimensional gesture, and a combination of sensing accuracy, power consumption and computational intensity.