🤖 fix: pin transcript during composer resize#3035
Merged
Conversation
Keep the transcript bottom pinned when the composer/footer resize changes the scroll viewport during send. Add a resize observer for the transcript viewport so auto-scroll stays anchored when the composer collapses before the matching user row and stream UI land in the transcript. Cover the regression with a UI test that simulates the viewport height change directly. --- _Generated with `mux` • Model: `openai:gpt-5.4` • Thinking: `high` • Cost: `$6.63`_ <!-- mux-attribution: model=openai:gpt-5.4 thinking=high costs=6.63 -->
Collaborator
Author
|
@codex review |
|
Codex Review: Didn't find any major issues. Keep it up! ℹ️ About Codex in GitHubYour team has set up Codex to review pull requests in this repo. Reviews are triggered when you
If Codex has suggestions, it will comment; otherwise it will react with 👍. Codex can also answer questions or update the PR. Try commenting "@codex address that feedback". |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Keep the transcript bottom pinned when send-time composer changes resize the chat viewport.
Background
Sending a message clears draft UI immediately, which can collapse the composer before the matching user row and stream-starting tail UI are appended to the transcript. Because the transcript and composer share a flex column, that footer collapse changes the transcript viewport height and can produce a visible jump while the transcript is re-pinned.
Implementation
ChatPanescrollToptoscrollHeightValidation
bun x jest tests/ui/chat/bottomLayoutShift.test.ts --runInBandmake static-checkRisks
Low. The new resize observer only forces bottom pinning while auto-scroll is enabled, so users who have intentionally scrolled away from the bottom should keep their current behavior. The change is limited to transcript viewport resizes, which is the send-time path that was producing the visible shift.
Generated with
mux• Model:openai:gpt-5.4• Thinking:high• Cost:$6.63