The scoped find walker wraps transcript text nodes in <mark> elements that
React does not own. Assistant responses stream through markdown-text.tsx,
which rebuilds the markdown DOM on every delta, and a new message is
appended whenever the assistant answers — so a re-render of a changed
region detaches the marks we inserted, dropping the user's highlights while
the bar stays open.
Watch the captured scope with a MutationObserver and re-wrap only when an
unmarked occurrence of the active query actually reappears. The observer is
gated behind a re-entrancy flag while the walker is mutating, coalesced to
one re-apply per microtask, torn down when the bar closes or the query
clears, and restores the active ordinal so a mid-stream re-render doesn't
reset the user's place to match #1. An append that adds no matching text is
a no-op; re-wrapping only fires when highlights genuinely went stale.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Chen Jin
c856c5f6db