fix(chat): stop dragging the viewport back to bottom while streaming (#811) - #843
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lifelmy wants to merge 1 commit into
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fix(chat): stop dragging the viewport back to bottom while streaming (#811)#843lifelmy wants to merge 1 commit into
lifelmy wants to merge 1 commit into
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Once the user scrolls up during a streaming turn, auto-follow now stays suspended until they return to the bottom, so streaming deltas no longer pull the viewport back down mid-read. Snap-to-bottom is gated on a follow-bottom flag maintained from real scroll events; the decision logic is extracted into pure helpers with regression coverage. Fixes org2AI#811 Co-authored-by: TRAE CLI <traecli@bytedance.com>
Neonforge98
marked this pull request as ready for review
August 20, 2026 05:08
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Summary
While a turn is streaming output, scrolling up to read earlier content was repeatedly dragged back to the bottom (#811). The message viewport snapped to the bottom on every streaming delta regardless of where the user had scrolled, so any upward scroll was undone on the next chunk.
This change makes auto-follow stateful: once the user scrolls up, following is suspended and stays suspended until they return to the bottom (or the container returns to the bottom on its own). Streaming deltas then leave the reading position stable.
Changes
MessageViewer.tsx: track afollowBottomflag from real scroll events; the snap-to-bottom effect now only runs while following (or already at the bottom). View/replay-window identity changes re-arm following so a fresh view starts pinned to the newest content, preserving the existing default behavior.MessageViewer/autoFollow.ts: new pure helpers (isViewportAtBottom,resolveAutoFollowOnScroll) that own the decision, so it is testable without a DOM/render environment.__tests__/autoFollow.test.ts: regression coverage proving an upward scroll suspends follow, repeated streaming growth keeps it suspended, returning to the bottom re-arms it, and a partial downward scroll does not re-arm.Test plan
pnpm exec vitest run src/modules/WorkStation/Chat/Communication— 97 passed (10 files), including the 9 new auto-follow tests.pnpm exec eslinton the changed files — clean.pnpm run typecheck(tsc --noEmit) — 0 errors.I have reviewed the design and implementation.
Fixes #811