Focus management

Dialogs, popovers, menus, tooltips, and command palettes share tabbable discovery, initial/fallback focus, containment, focus-by-ID, and restoration. A modal dialog focuses the requested connected target, then the first tabbable descendant, then its content container with tabindex=-1.

Tab containment wraps first/last focus and handles an empty scope. Restoration is attempted only for a connected, enabled target. Removing a trigger before close is therefore safe. Collection widgets may use roving DOM focus or aria-activedescendant; their item traversal remains in the collection layer.

The consumer must render a logical DOM order and visible focus indicator.

Tabbable discovery is scoped to the supplied container and does not cross into descendant shadow roots. A custom element that owns focusable shadow content must expose a suitable host focus target or provide focus behavior in its integration layer. Outside-interaction checks do use composed event paths, so declared overlay branches can span open shadow boundaries.