twoway contour automatically generates a colour scalebar where there is colour information in the plot.

How do I suppress it? It's not a legend, so legend(none)

. twoway contour z y x, interp(none) levels(20)
gives this:
Array

The scalebar corresponds to the z-dimension, so doing stuff with zlabel() has some effect:
. twoway contour z y x, interp(none) levels(20) zlabel("")
gives this:
Array

So we lose the labels, but I can't see any way to get rid of the bar.

Any ideas?

Brendan