one of UPDATE_ALWAYS , UPDATE_CONTINUOUS , UPDATE_DELAYED , UPDATE_DISCONTINUOUS and UPDATE_IF_VALID .
The default policy is GTK.UpdateContinuous which means that the
current color is updated continuously when the user drags the
sliders or presses the mouse and drags in the hue-saturation wheel
or value bar. If you experience performance problems, you may want
to set the policy to GTK.UpdateDiscontinuous or GTK.UpdateDelayed.