Is it possible to get/set the z-order of Windows?

Our application saves & recalls the state (positions, dimensions) of the Window objects in a particular View. All works well, except when the Windows overlap - because we don’t save the z-ordering of the Window objects yet. That is because I couldn’t find an API by which to get this information. Am I missing something? If not, has someone written an enhancement ticket for this that I could vote for?

Thanks for all information,
Thomas Wolf