Is there an html or WCAG definition of "modality" as it relates to keyboard behavior in a modeal dialog?

Greetings

At a meeting with a big client today we had exhaustive discussions on
whether it is a failure if user focus is allowed to go out of a modal
dialog, into the address bar of the browser, then back into the modal.
The big issue discussed is that no one was able to find a W3C
definition of modality. The ARIA Authoring Guide describes expected
behavior when navigating a modal dialog using the keyboard, but that
specification, though excellent, is not normative.
It is not clear to me that allowing user to get to the address bar is
a definitely violation of 2.4.3 (I would like to find something that
enabled me to definitely call it as such).
Apologies if this is off-topic, but is there anywhere in WCAG specs or
the html spec where modal is clearly defined with regard to keyboard
navigation, something that can be referenced when calling keyboard
navigation that enables user to leave a modal, if only for a single
tabstop, a WCAG failure?
Thanks
-Birkir

Received on Wednesday, 15 April 2015 19:22:34 UTC