How do you obtain the tab names for a Simulink 2013b mask parameter?

After selecting the appropriate simulink block and using the commands

p = Simulink.Mask.get(gcb);
p.Parameters(1).TabName;

I should, according to the documentation, get the name of the tab containing parameter 1. The returned value is always empty. The returned Simulink.MaskParameter object does not contain a TabName field even though the mask clearly contains a tab with the parameter under it.

Also tried using get_param(gcb,'MaskTabNames') but it just returns a cell array of empty strings. The documentation states this property is for "internal use only" but it always returned the list of tab names under earlier versions.

Given that neither of these methods work how does one obtain the tab name associated with a mask parameter?

Thanks in advance.