Smooth scrolls toward the bottom (new-message arrival in Effect A and the
Jump-to-Present click) animate scrollTop over many frames. Each intermediate
handleScroll measurement saw a large distanceFromBottom and flipped
isAtBottomRef to false, closing the Effect B/C gates. Lazy media (avatars,
embeds, Spotify thumbs) finishing mid-animation grew scrollHeight while the
gate was closed, so the smooth scroll landed at its originally-computed
target — leaving the user above the new bottom by ~the height of what loaded.
Fix: typed smoothScrollIntentRef ('bottom' | 'message' | null) with an 800ms
deadline. handleScroll suppresses the at-bottom flip while intent is 'bottom'
and the user hasn't wheeled past the 5000px nearBottom threshold. Effect D
fires a final defensive instant pin via native scrollend (Chrome 114+,
Safari 18+) or a setTimeout(800) fallback. 'message' intent (jump-to-message
from search) does NOT suppress — the gate flips honestly so the user is left
at the targeted message.
Verified live on nova.ddns.net Orbit → general: Jump-to-Present
lands flush at bottom; new Spotify-link messages stay at bottom as embeds
arrive via WS. docs/systems/message-list.md updated.
Jannis Braun
b6b830568c