A non-`auto` `scrollbar-width` or `scrollbar-color` makes Chromium and Safari
discard every `::-webkit-scrollbar*` rule for that element, including
`::-webkit-scrollbar-thumb:hover`. Declaring both unconditionally left the
hover tokens rendering nowhere: the engines implementing the hover
pseudo-element are exactly the ones the standard properties silence, and
Firefox has no hover pseudo-element to fall back on. Both hover tokens and all
four elevated surfaces' hover rebinds were therefore dead code.
Measured in chromium on probe elements with `scrollbar-gutter: stable`: an 8px
`::-webkit-scrollbar` alone reserved a 30px band, and adding
`scrollbar-width: thin` dropped it to the 10px `thin` reserves.
The standard properties now sit inside `@supports not
selector(::-webkit-scrollbar)`, so Firefox takes them and WebKit-based engines
take the pseudo-elements. The WebKit rules stay ungated: an engine without
those pseudo-elements drops them as unknown selectors, and gating them would
hide them from an engine that implements them without `selector()` — the
pre-16.4 Safari the ungated form serves correctly.
Three unit assertions pin the split by source offset, which the existing
at-rule-flattening parser cannot see. The web e2e now reads the path chromium
actually takes: the `auto` standard properties as the gate's signature, the
pseudo-element sizing and track, the indirection variables resolved per
throwaway probe, and the hover declaration as cascade rule text — chromium
folds the `:hover` rule into `getComputedStyle(el,
'::-webkit-scrollbar-thumb')`, so no computed query separates the states.
Review follow-ups: the three new notify loops (currentProvideInfo
subscribers, ui-skill lexicon listeners, late-registration controller
setup) now contain per-callback failures so one faulty consumer cannot
starve the rest, abort the list projection pass, or poison the source
roster with no disposer; controller lexicon polling drops a throwing
source with a console record like the candidate path. The ui-slash
README (both languages) now states the late-registration warm and the
subscribeLexicon contract, and the scenario suite drives a typed /name
token gaining its decoration when the roll settles with no further
input.
provideInfo(id)/maybeProvideInfo(id) lost their last external caller
when the renderer host switched to the currentProvideInfo observable;
both become private (tests assert through the public projection). The
reprojection method's name now says what it does — re-derive and
publish on change — and matches the field family it maintains.
Registrant-private reactive facts previously reached components as raw
observables that each component subscribed by hand (InputBar notices/
lexicon via uSES, SettingsRoot via a version/subscribe/getter triple).
The inject face now carries a reserved hooks compartment of bare
sources; the renderer binds each into a use<Name> selector hook through
the same machinery as the provide channel, so components consume
useNotices/useLexicon/useSections and never see a subscription
primitive. InputBar and SettingsRoot are the first two consumers.
The decoration scan read a mutable lexicon() aggregation during render
with no subscription, so a catalog settling or a child spawning after
prewarm left drafted tokens undecorated until an unrelated re-render.
The controller now publishes the aggregation as a snapshot store fed by
a new optional SlashSource.subscribeLexicon hook (ui-skill notifies on
settle/invalidate, ui-subagent forwards the session-list feed), the
composer keyboard face exposes it as an observable, and InputBar
subscribes through uSES. Sources registered after scope birth now warm
and join live controllers via a service broadcast.
The manual useState+useEffect subscription could miss a registration
landing between render and effect commit; uSES closes that window and
keeps the same version-dedupe behavior.
A provider roster change under a stable current id rematerialized every
scope's bundle but nothing notified React: SessionProvider resolved the
bundle from a current-id subscription only, so mounted entries kept the
obsolete hook/prop schema until an unrelated re-render. The sessions
service now owns an atomic currentProvide observable fed by both current
writes and roster changes; the renderer host exposes it as
sessions.provide, replacing the current/provideInfo/maybeProvideInfo
trio, and both providers subscribe to it.
Verifying browser-visible plugin CSS needs a rebuild build:web does not
perform: WorkspaceBrowser.module.css never reaches apps/web/dist, because
ui-workspace loads as a runtime plugin with its CSS inlined into
lib/client.js by that package's own bundle script. A negative control that
reruns only build:web exercises a stale bundle and passes with the
declaration removed, which reads as a vacuous test rather than an invalid
control. No script in the web lane does this rebuild, so every scroll-region
or plugin-CSS change hits the same trap.
Every scaffold-importing e2e compiles on the host plane, so the new file
goes in tsconfig.host.json's include list and apps/web/tsconfig.json's
exclude list. Without both, tsc -p apps/web/tsconfig.json fails with
TS6059/TS6307.
design-platform.css declared four --dsw-alias-scrollbar-* tokens in both
palettes that no rule read, so every scrolling region rendered the user
agent's own scrollbar and the dark theme showed a light native bar against
dark surfaces.
The symptom that surfaced the gap was in the sidebar: the workspace
browser's session list is its only scrolling region, and each row's
trailing content (the relative timestamp, and the hover action buttons
that replace it) is `flex: none` flush against the row's 8px right
padding, so an overlaid scrollbar painted on top of the timestamp.
ui-theme/styles/scrollbar.css becomes the sole consumer of the four
tokens, imported by the web shell's base.css after design-platform.css
because it reads that sheet's tokens. The rules sit on `body`, not
`html`: the alias tokens are declared on `body`, custom properties
inherit only downward, and from `html` they resolve to the
guaranteed-invalid value with scrollbar-color computing to `auto`.
scrollbar-width and scrollbar-color are declared on `body, body *` rather
than inherited, because inheritance would carry the color already
substituted at `body` and an elevated surface could not retint its own
thumb; scrollbar-width does not inherit at all.
Both the standard properties and the ::-webkit-scrollbar pseudo-elements
read one indirection pair bound to the l1 tokens, so an elevated surface
rebinds that pair to the l2 tokens once and retints both renderings. The
command popup, slash menu, model-select panel, and settings panel do so,
which gives the l2 tokens their first consumers.
WorkspaceBrowser's `.list` declares scrollbar-gutter: stable, keeping the
bar beside the rows. `stable` rather than `auto` so the reservation holds
when the list is short enough not to scroll: expanding a workspace group
would otherwise shift every row sideways at the moment it starts
scrolling.
