Three Dimensional User Interface Session Control

A method, including receiving, by a computer executing a non-tactile three dimensional (3D) user interface, a set of multiple 3D coordinates representing a gesture by a hand positioned within a field of view of a sensing device coupled to the computer, the gesture including a first motion in a first direction along a selected axis in space, followed by a second motion in a second direction, opposite to the first direction, along the selected axis. Upon detecting completion of the gesture, the non-tactile 3D user interface is transitioned from a first state to a second state.