Owner report + live [ui-hover] probe (2026-08-24): hovering a
content-fits scrollbar did nothing because IsModelDisabled made the
whole bar hit-TRANSPARENT — every hover over it reported
widget=<none>. Retail's arrows and thumb are real child elements whose
Normal_rollover hot-tracking keeps running while the scrollbar is
disabled (UpdateLayout @0x004710d0 only hides the page-click regions,
children 4-7, and — with attribute 0x79 — the whole bar); scrolling
stays inert through geometry, not an input gate: a full-track thumb has
zero travel and the line/page steps clamp against nothing.
OnHitTest and the input path now gate on presentation visibility only.
A visible disabled bar hover-highlights and consumes clicks without
scrolling; a HideWhenDisabled bar stays inert. New root-level hover
tests drive real UiRoot hit-test dispatch (bare widget + the mounted
production character fixture) so this class of "state machine green,
pointer never arrives" bug fails loudly.
User-verified live 2026-08-24 ("bar works now").
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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