A rail that was open over the page left it on `transition: … display …
allow-discrete`: the compact adaptive rail's slide-out, the slide-out of
a rail that hides when collapsed, and every rail scrim's fade. Firefox
does not transition `display`, even with `allow-discrete` (Chrome 117
and Safari 18 do), so there the panel and the scrim vanished on the
first frame. Unlike the sheets' scrims these are drawn by attribute
rules on `data-md-open`, not `x-show`, so Alpine had nothing to hold.
navigation.js now marks a rail that closes `data-md-closing` — `sheet`
when the panel leaves the window, `scrim` when it stands in the layout
again — and drops it once the panel's `translate` and the scrim's
`opacity` transitions have finished (at once under reduced motion, or
when the rail opens again). navigation-rail.css keeps what is leaving
displayed, and a sliding panel in its open geometry, while the
attribute is set, and no longer transitions `display` anywhere, so
Chrome and Safari do not hold a second time. The view sets it from
`x-effect`, beside the `x-bind` that drops `data-md-open`, so both
attributes change in one flush: a `$watch` a microtask later let a
style read in between settle the scrim as already hidden. The collapsed
branches and `--md-navigation-rail-value` are untouched.
NavigationTest samples each exit part-way in the page (the compact
slide, the hide-when-collapsed slide, a modal rail's scrim) and checks
it ends hidden; all three fail on main in Firefox and pass in Chrome,
Firefox and Safari. They wait for the entry to finish first: Firefox
creates a transition on its next refresh tick, so straight after a
change its computed style already reads the end value. NavigationRailTest
pins the holds and that no rule transitions `display`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
