[teamleaderleo]

Leo, 2026-10-31, on a screenshot of a chat's file-changes review drawn over the middle of the chat: "AND WHY THE FING DOES IT STILL NOT FING OPEN TO THE RIGHT". His placement rule from the same day: "just open it on the existing. you only need the rightmost bottom auto split when there's a terminal that gets opened when there's already a browser, and vice versa". In short, the changes open on the right, never over the chat.

Why it still floated

A chat's View changes has two paths (openDiff in App.tsx):

1. diffBeside opens the folder's git diff in its own native pane right of the chat (Lawrence, 2026-10-13: "when i click diff viewer it opens in new pane to right"). That path works only when the chat folder is a repository and every file the turn wrote is inside it.
2. Otherwise the turn's own diff opens in the page (cmux NEXT: a one-file Edited card expands to its diff; View changes shows new and out-of-repo files #23161 added this fallback for new and out-of-repo files). That is Leo's case: the chat runs in ~/Projects, which is not a repository, and the turn wrote to ~/.claude/.../memory/*.md.

The in-page view went beside the transcript only when the pane was at least 1160px wide (@container (min-width:1160px) in header/header.css, from #17556, "as in the Codex app"). In a narrower pane, styles.css hid the transcript and the chat header (visibility:hidden), and the panel (position:absolute; inset:0) covered the chat. Earlier right-side work (#28989 and #28044 on lower-right placement, #29080 on MCP open placement) changed only the native pane path, so it never reached this fallback. That is why the bug "still" showed.

Changes

• header/header.css: the in-page changes view sits right of the transcript at every width. The chat keeps 44% of the pane, and at least 320px when the pane is 640px or wider (--acpmux-review-chat). No container or media query decides this any more.
• styles.css: opening changes no longer hides the transcript or the chat header.
• The red banner "The branch state could not be read. Refresh and try again." came from the view's Commit and Push status read (git.status). For a folder outside a repository, the session host answers operation.failed with details.extra.code: not_a_repository, and useGitWrite treated that as a failed read. Now isNoRepository (in changes/gitWrite.ts) marks that answer as "no repository". The view then offers no Commit or Push and shows no error. Other failures (timeouts, git errors) still show the banner with Refresh. The native diff page uses the same hook and now behaves the same way.

Test

webviews/test/agent-pane-changes-placement.test.tsx:

• The .acpmux-reviewing>.acpmux-diff-panel rule sits at the top level, inside no @container or @media, and places the panel at --acpmux-review-chat. The transcript gets the matching right margin.
• No pane sheet hides .acpmux-reviewing>.acpmux-scroll or .acpmux-header.
• isNoRepository accepts not_a_repository and rejects timeouts and git failures.
• useGitWrite with a not_a_repository status: statusFailed false and available false. With a timeout: still statusFailed.

Command: cmux-ci test -- bash -c 'cd webviews && bun test test/agent-pane-changes-placement.test.tsx test/diff-viewer-git.test.tsx test/changes-status.test.ts && bun run check'

Observed / Not run

• Observed: on the fleet Linux run of 330b0d3, 17 pass and 0 fail, and vp lint and the type check were clean. vp fmt flagged 2 files; b56ca15 formats them, and vp fmt --check now passes.
• Red on the base: the test commit (25551f9) comes before the fix. It fails on the base because isNoRepository does not exist there, and the CSS assertions describe rules the base does not have. I did not run it separately on the fleet.
• No native capture: this changes webview CSS only. Leo will try the build himself.

Risk: normal. Webview-only (CSS plus one hook). The in-page view now shares the pane with the chat in a narrow pane instead of covering it.

Changelog

Fixed: A chat's file changes open on the right, beside the chat, at every pane width, and a chat in a folder that is not a git repository no longer shows "The branch state could not be read."

Agent session: agent session

🤖 Generated with Claude Code

---

^{Need help on this PR? Tag @codesmith-bot with what you need.}

---

Summary by cubic

Fixes the chat's file changes view so it always opens on the right, beside the transcript, instead of covering the chat in panes under 1160px wide. Also stops chats in folders that are not git repositories from showing a "The branch state could not be read" error.

• The changes panel and transcript now share the pane at any width; the chat keeps 44% of the pane (at least 320px when the pane is 640px or wider). A browser test now covers the narrow-pane case.
• A not_a_repository status read no longer counts as a failure: the view hides Commit and Push and shows no error, while timeouts and git errors still show the banner with Refresh.

^{Written for commit 1a98382. Summary will update on new commits.}

[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review c7f5a27: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr29672 -f ref=fix--changes-review-opens-right -f platform=macos -f backend_mode=local

Gallery before/after for 3d5f7fa: 16 states rendered, 0 images differ, 1700 more touched states not rendered. Images are in the run's artifact, not on this public PR; the independent review of this head reads them on its own, so the PR needs no hand-made screenshots of these states.

gh run download 41244220688 -R manaflow-ai/cmux -n gallery-advisory-29672-3d5f7fa966bfde91467e5a705ba475c95e84f114 (then read gallery-review.json)

States

State	Theme	Status	Diff	Picked by
agent-pane.access-offer/turn-no-credits	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.access-offer/turn-no-credits	Apple System Colors	unchanged	0%	own styles.css
agent-pane.access-offer/turn-low-credits	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.access-offer/turn-low-credits	Apple System Colors	unchanged	0%	own styles.css
agent-pane.access-offer/turn-no-offer	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.access-offer/turn-no-offer	Apple System Colors	unchanged	0%	own styles.css
agent-pane.add-project-panel/environment	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.add-project-panel/environment	Apple System Colors	unchanged	0%	own styles.css
agent-pane.add-project-panel/sources	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.add-project-panel/sources	Apple System Colors	unchanged	0%	own styles.css
agent-pane.add-project-panel/directory	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.add-project-panel/directory	Apple System Colors	unchanged	0%	own styles.css
agent-pane.add-project-panel/keyboard	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.add-project-panel/keyboard	Apple System Colors	unchanged	0%	own styles.css
agent-pane.add-project-panel/browse-error	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.add-project-panel/browse-error	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-failed	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-failed	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-recovered	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-recovered	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-empty	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-list/page-empty	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-loading/first-page	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-loading/first-page	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-loading/indexing	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-loading/indexing	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-loading/loaded	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-loading/loaded	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-loading/empty	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-loading/empty	Apple System Colors	unchanged	0%	own styles.css
agent-pane.all-chats-loading/failed	Apple System Colors Light	unchanged	0%	own styles.css
agent-pane.all-chats-loading/failed	Apple System Colors	unchanged	0%	own styles.css

_{Pick other states with a Gallery: entry.id, entry.id/variant line in the PR body.}

Passes: CI passes on c7f5a27bba.

CI passes on c7f5a27bba (run 41303431007 attempt 1).

Written by scripts/ci/classify_failures.py (ci-failure-attribution.yml); signatures are its SIGNATURES table. A machine verdict is the runner's fault, not this PR's; yours means the failing file is one this PR changes, also red on main that main's latest full suite fails the same way, seen on other PRs that it failed on another pull request's run lately.

web and size checks: green

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4131746817401 (af670df60f)
• cmux NEXT nightly 1.0.0-nightly.4131829275601 (829d1467c6)
• cmux NEXT nightly 1.0.0-nightly.4131862054001 (593b25f9f6)
• cmux NEXT nightly 1.0.0-nightly.4131908227901 (ab8c3a2196)
• cmux NEXT nightly 1.0.0-nightly.4131981731501 (b1ad117968)

[teamleaderleo]

Owned by an agent session · session

[cursor]

Bugbot needs on-demand usage enabled

Bugbot uses usage-based billing for this team and requires on-demand usage to be enabled.

A team admin can enable on-demand usage in the Cursor dashboard.

[teamleaderleo]

Review (codex gpt-6-astra high, next-review): SHIP at 3d5f7fa

SHIP at 3d5f7fa

Visual verdict: The 16 supplied after/before gallery pairs are pixel-identical and contain no changes-panel state, so the new split is not visually exercised.

1. [P1] [follow-up] isNoRepository misses errors from the native diff page. diffGitSource passes PageClient errors directly, whose resource details are wrapped as {origin, details: {...extra...}}; the predicate only checks error.details.extra at gitWrite.ts:150. Therefore an out-of-repository git.status in the native diff viewer still sets statusFailed and shows the branch error. Unwrap the page error details or add a PageError-path test.

Follow-ups:

• [P1] Fix isNoRepository handling for the native diff page’s wrapped PageClient errors.

[cmux-bot]

cmux-bot approves 3d5f7fa: an independent review passed this exact head (next-review receipt by teamleaderleo). A push needs a new review; a later BLOCK at this head dismisses this approval.

[teamleaderleo]

Awareness note from an agent lane that does not own this PR; it is not a review or a request to take the PR over.

---

Carried in #29904: this PR's commits unchanged, plus a base merge that resolves the styles.css conflict with #29618. That conflict blocked this PR from landing. This PR stays open for its owner to close.

[teamleaderleo]

Awareness note from an agent lane that does not own this PR; it is not a review or a request to take the PR over.

---

Landed as #29904 (this PR's commits plus a base merge resolving styles.css).

[blacksmith-sh]

Found 7 test failures on Blacksmith runners:

Failures

Test	View Logs
main.DeveloperIdAppTests.test_download_prints_the_active_profile_only/ test_download_prints_the_active_profile_only	View Logs
nightly must build and hand off the macOS 26 helper and Xcode 26.5 app before publishin g/ nightly must build and hand off the macOS 26 helper and Xcode 26.5 app before publishin g	View Logs
stubs: /System/Library/Frameworks/Security.framework/Versions/A/Security has no stub/ Security has no stub	View Logs
stubs: CoreFoundation.tbd: install-name /System/Library/Frameworks/ CoreFoundation.framework/Versions/A/CoreFoundation, missing 1: ['_CFRetain']/ CoreFoundation, missing 1: ['_CFRetain']	View Logs
stubs: CoreFoundation.tbd: install-name /System/Library/Frameworks/ CoreFoundation.framework/Versions/A/CoreFoundation, missing 1: ['_log2']/ CoreFoundation, missing 1: ['_log2']	View Logs
test_helper_never_takes_a_hosted_mac_and_skips_compile_on_hit (main.WorkflowTests.t est_helper_never_takes_a_hosted_mac_and_skips_compile_on_hit)/ test_helper_never_takes_a_hosted_mac_and_skips_compile_on_hit (main.WorkflowTests.t est_helper_never_takes_a_hosted_mac_and_skips_compile_on_hit)	View Logs
test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)/ test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)	View Logs

^{Need help on this PR? Tag @codesmith-bot with what you need.}

[teamleaderleo]

Review (codex gpt-6-astra high, next-review): SHIP at 1a98382

SHIP at 1a98382

Visual verdict: no images; Leo tries the build

No correctness findings.

Follow-ups:

• [P2] [follow-up] No after screenshots were provided, so visual verification remains pending.

[cmux-bot]

cmux-bot approves 1a98382: an independent review passed this exact head (next-review receipt by teamleaderleo). A push needs a new review; a later BLOCK at this head dismisses this approval.

A newer verdict blocks c7f5a27 (no independent SHIP at the head).

[teamleaderleo]

Review (codex gpt-6-astra high, next-review): SHIP at c7f5a27

SHIP at c7f5a27

Visual verdict: no images; Leo tries the build

1. [P2][follow-up] The mock outside-repository status path still throws a plain Error at mockGit.ts:106. Since isNoRepository only accepts the structured machine error at gitWrite.ts:149, ?mock still shows the branch failure banner and Git controls for the dotfiles fixture. Make the mock emit details.extra.code: "not_a_repository" and add coverage.

Focused Bun tests could not run because Bun is unavailable in the review box.

Follow-ups:

• [P2][follow-up] Align the mock status error with the native not_a_repository response.

[cmux-bot]

cmux-bot approves c7f5a27: an independent review passed this exact head (next-review receipt by teamleaderleo). A push needs a new review; a later BLOCK at this head dismisses this approval.