The platform's FloatingPortal targeted <body>, which is painted UNDERNEATH whatever
holds the fullscreen lock. That is why the player's in-bar menus were either
non-portaled (and clipped) or, for add-to-playlist / download, disabled outright in
fullscreen. PopoverSurface now portals into `document.fullscreenElement` while one
exists, via a new reactive `useFullscreenElement()` on the existing WebKit-aware
fullscreen lib.
Two floating-ui details this had to work around: a null `root` means "the container
does not exist yet" (no portal node is created at all), so the no-fullscreen case must
pass undefined; and the portal node is built once and ignores a later root change, so
the portal is keyed on the fullscreen state to remount on a transition.
Migrated the three hand-rolled hover engines onto the platform:
- Tooltip: kept as a passive caption via a new `passthrough` prop on PopoverSurface,
so it cannot swallow a click aimed at a control it overlaps during the close delay.
Gains aria-describedby wiring it never had.
- AboutCell: the 160 ms hide-timer hover bridge is now safePolygon; the close-on-page-
scroll is now hide-and-follow, so the card reappears when the row scrolls back.
- TagManager: same bridge removal; the scroll-fade moves to an inner scroller so the
mask rides the scrolling box rather than the glass panel.
Verified in-browser: tooltip flip + centering + pointer-transparency, About card flip-
above with the measured height, tag popover right-start anchoring, and the portal
round-trip body -> fullscreen element -> body on a live fullscreenchange.
peter
2756c21dbd