h=scatterhist(__) returns a 1x3 vector of axis handles for the [scatter axis, marginal x axis, marginal y axis].
To turn off/on the visibility of the marginal histograms/boxplots
To turn the marginal axes off/on
By default, the marginal axes are off and the objects in the axes are still visible.
To permanently delete the marginal axes
Note that a listener that responds to changes in the axes assumes the marginal axes exist and will throw a warning if your make certain changes to the figure after removing a marginal histrogram axes. For this reason, the first option above is better.