Expose a dialog as modal / non-modal

[scottaohara]

As an open item for discussion per dialog initial focus, a proposal should the dialog role be adjusted to expose whether it is a modal or non-modal dialog? Whether that be by use of aria-modal or the native dialog element's .show() method and open attribute toggling (non-modal), vs the showModal() method which explicitly makes the dialog modal.

[DavidMacDonald]

I agree... would be good to specify modal/non-modal natively.