Motivation

Currently, AriaModalController in the overlay uses this as which refers to the vaadin-overlay element. This can be problematic with the native popover as the actual overlay will be in shadow DOM and the content will be slotted into it, which therefore will also set aria-hidden on the content.

Proposed solution

Update usage of AriaModalController() to pass the callback option which allows customizing the actual elements that need to remain interactive while hiding others with aria-hidden, and then add protected property e.g. _modalRoot which in case of native popover could point to e.g. the overlay owner.

Prototype: https://github.com/vaadin/web-components/compare/refactor/overlay-modal-root