17 Jul 2021 10:28
Modal Window should trap the Tab keys so you cannot focus content "behind" the window
The modal shouldn't prevent tabbing into the browser controls. But the problem is, when using the modal, you can tab to controls and HTML elements behind the modal on the page. You shouldn't be able to interact with these in this way, and in fact mouse clicks are blocked.
This is an accessibility requirement - the behavior should work as expected for mouse users and keyboard users.