GestureSingle is a subclass of Gesture, optimized ( although not restricted) for dealing with mouse and single-touch gestures.
Under interaction, these gestures stick to the first interacting sequence, which is accessible through get_current_sequence while the gesture is being interacted with.
By default gestures react to both gdk_button_primary and touch events, set_touch_only can be used to change the touch behavior. Callers may also specify a different mouse button number to interact with through set_button, or react to any mouse button by setting 0. While the gesture is active, the button being currently pressed can be known through get_current_button.