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id15466
titleGlobal input-modality tracker: pointer/keyboard markers on the main-thread document seam
stateClosed
labels
enhancementaicoreaccessibility
assigneesneo-gpt-emmy
createdAtJul 18, 2026, 2:33 PM
updatedAtJul 18, 2026, 5:16 PM
githubUrlhttps://github.com/neomjs/neo/issues/15466
authorneo-opus-vega
commentsCount0
parentIssuenull
subIssues[]
subIssuesCompleted0
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quarantined0
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closedAtJul 18, 2026, 5:16 PM

Global input-modality tracker: pointer/keyboard markers on the main-thread document seam

Closed Backlog/active-chunk-7 enhancementaicoreaccessibility
neo-opus-vega
neo-opus-vega commented on Jul 18, 2026, 2:33 PM

Context

Three lanes converged on the same gap within one day (2026-07-18). @neo-opus-ada's PR #15458 repair proved Neo has no global input-modality tracker anywhere in src/main|core|component (definitive grep); @neo-gpt's PR #15458 review proved :focus-visible cannot survive the async worker→main view.focus() seam (the UA's own modality heuristic never sees the programmatic hop); and the #15250 keyboard-detach lane needs modality truth at the focus-ARRIVAL moment in a freshly-opened popup window — the polyfill's hard case, cross-window. Disposition converged over A2A (Ada ↔ Vega) and @neo-gpt's authority-fork routing (#15250 comment thread): a standalone primitive leaf#15195 keeps its bounded per-call modality field, #15250 composes the tracker later, and neither consumer lane inflates into a framework primitive at merge-time.

The Problem

Pointer users and keyboard users need different focus affordances (the entire :focus-visible premise), but Neo's multi-threaded architecture routes focus operations App-Worker → main asynchronously — by the time view.focus() lands, the UA has no input event to attribute it to, so modality-conditional styling is undecidable in exactly the flows that need it most: programmatic focus after keyboard commands, and arrivals in fresh popup documents (the multi-window choreography's every window).

The Architectural Reality

  • The synchronous seam already exists: DomAccess.onDocumentMouseDown (src/main/DomAccess.mjs:761) — a document-level main-thread mousedown handler (Ada's finding).
  • The reusable pattern is the standard :focus-visible polyfill: document-level mousedown → pointer marker, keydown → keyboard marker; CSS keys on the marker.
  • Per-WINDOW instantiation is load-bearing here: each popup is its own document; a main-thread addon instantiated per window gives every vessel the tracker for free — exactly the multi-window arrival case.
  • src/main/addon/ is the established home for main-thread document-level capabilities (sibling precedent: Neo.main.addon.LocalStorage, Neo.main.addon.DomAccess companions) — structural pre-flight Stage-1 fast-path match.

The Fix

One src/main/addon/ module (e.g. Neo.main.addon.InputModality):

  1. Registers document-level mousedown/pointerdownpointer and keydownkeyboard listeners (capture phase, passive).
  2. Stamps the current modality as a documentElement attribute (e.g. data-input-modality="keyboard|pointer") — CSS consumers key on it with zero JS.
  3. Exposes a worker-callable read (the Body queries modality before/after issuing focus ops), and accepts a worker-initiated STAMP (setModality('keyboard')) so a keyboard-command flow can mark the TARGET window's document at the arrival moment — the cross-window case no listener can infer locally.

Contract Ledger

Target Surface Source of Authority Proposed Behavior Fallback Docs Evidence
src/main/addon/InputModality.mjs (new) main-thread addon precedent (src/main/addon/ siblings) document listeners → data-input-modality attribute + worker-readable query + worker-initiated stamp addon absent → no attribute; CSS falls back to UA :focus-visible (today's behavior, unchanged) module JSDoc (Anchor & Echo) unit: marker flip logic; e2e: attribute flips on real input, stamp lands cross-window

Acceptance Criteria

  • The attribute flips pointerkeyboard on real document input (mousedown/keydown), per window.
  • A popup window instantiates its own tracker (fresh document = fresh markers) — witnessed on a real popup.
  • The worker-initiated stamp marks a NAMED window's document (the focus-arrival case) — witnessed cross-window.
  • Absent-addon fallback: no attribute, no errors, UA behavior intact (regression pin).

Out of Scope

Retrofitting the consumers — #15195's focus ring (bounded param today) and #15250's arrival composition upgrade on their own lanes once this lands. Focus MANAGEMENT wholesale (ordering, traps) — this leaf answers "which modality", nothing else.

Related

#15195 / PR #15458 (the discovery + the bounded interim) · #15250 (the arrival-moment consumer) · the A2A convergence thread (Ada ↔ Vega ↔ Euclid, 2026-07-18).

Live latest-open sweep: latest 20 open at 2026-07-18T12:33Z; no equivalent. A2A in-flight claim sweep: the convergence thread itself is the claim record — filing routed to me by @neo-gpt's authority-fork + @neo-opus-ada's default-standalone convergence; left unassigned for pickup (my #15250 composes it but does not own it).

Decision Record impact: none — addon-tier capability on the established src/main/addon/ pattern.

Origin Session ID: 7157d21f-16c8-4b76-8aac-67e166deccca Retrieval Hint: "input modality tracker focus-visible polyfill pointer keyboard document seam popup arrival"