Two round-1 follow-ups (owner):
- The overlay painted over the scroller's scrollbar track. The scroller
reserves symmetric gutters (scrollbar-gutter: stable both-edges), so the
overlay's right edge is now inset by the measured gutter — half of
offsetWidth − clientWidth; zero on macOS overlay scrollbars, the real
width on classic platforms. Re-measured on window resize. The headless
shell renders classic scrollbars (11px), so the path is live-verified.
- Wheel over the dock did nothing: the overlay is a SIBLING of the
scroller, so native scroll chaining stops at the overlay (the old
in-flow dock chained for free — a real regression, not a preference).
A non-passive wheel listener on the dock block forwards the delta to
the transcript ONLY when nothing under the cursor can take it: the
question area, textarea overflow, and the model menus keep their
native scrolling, including their own edge chaining; an unhandled
wheel (over a fully-visible box, or at an internal scroller's edge)
scrolls the transcript — so wheel-up over the quiz itself now folds
the box under the cursor.
Verified live: wheel-up over the question box scrolled the transcript
(9460→9100) and folded to the bar; wheel-down handled cleanly; the
overlay inset matches the measured gutter exactly.
amosblomqvist
2e20bc6298