[lawrencecchen]

Summary

cmux-ad m6 1b, the switch deletion. #35195 landed the interim browser contract for key resizes behind browserResize.keyResizeTopLeft (default on). Its OFF/ON film passed (the refactor owner's STATUS 11746: with the switch on, the page's left and top edges are on the pane edge in every motion frame of px-keys-single-3k and px-keys-held-2; off 50-248 frames off). STATUS 11198 says the switch goes once that film passes. No behaviour change with the default on.

Frames: no content kind changes what it shows in any frame (the default-on path is the only path now).

Removed:

• BrowserResizeTunables.keyResizeTopLeft (Debug Settings > Browser Resize) and its entry in BrowserResizeTunables.all.
• CEFTabContentView.pageHoldTopLeft and its latch in holdPage(for:).
• The off path: a key hold's page on S3's hold edges (the pane edges that do not move). CEFTabContentView.layoutContent places a held page, a drag's or a key hold's, at the page frame's top-left corner. pageMotionHold still marks a key hold (its resume after the tab is hidden and shown, and a drag's end not ending it). Its edges no longer place the page.

schemas/defaults/cmux-next.json is not edited by hand: the base autofix regenerates it.

Merge timing: after the first FEAT DOGFOOD BUILD with #35195 is judged by the P0 JOURNEY RUNNER, as for S3's switch (#35161), unless the refactor owner says sooner.

Testing

No new test: CEFDeferredTabShowTests.aKeyResizeHoldKeepsThePageOnThePageAreasTopLeft (#35195's red-first test) covers the one path.
Fleet green at this head: step 8259737de704222f1337b39c (CEFDeferredTabShowTests, BrowserChromePaneMotionParkTests, BrowserChromeSharedEdgeTests, BrowserPaneOneContainerTests, PaneContentPolicyTests, KeyboardResizeContentHoldTests, InternalPageParkingTests): 7 of 7 suites passed.

Changelog

none

Proof

No capture: no behaviour change (a switch and its off path deleted).

Observed / Not run

Observed: the fleet step above.
Not run: films (no behaviour change with the default on, which the films already judged).

[github-actions]

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

Review e389a72: 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=pr35382 -f ref=fix/browser-delete-keyresize-topleft -f platform=macos -f backend_mode=local

red: cmux-next checks (god files, concurrency, crash safety, l10n); no finished base run on b1b0f37 to compare; do not merge until green; see lane-rules

Default changes

This pull request changes 2 defaults at e389a7212f36 (what everyone gets without configuring anything):

• tunable-source.CmuxNextBrowser/Core/BrowserResizeTunables.swift:keyResizeTopLeft: "193b05abe6108e339e570d48352b341a6165f3385ea9939b6a062612faaf3193" -> (none)
• tunable.browserResize.keyResizeTopLeft: true -> (none)

Signed off on this commit by review (codex).

Regenerate the snapshot with python3 scripts/ci/defaults_guard.py snapshot.

[lawrencecchen]

Review (codex): SHIP at e389a72

Reviewer: Codex (gpt-6.1-sol), codex exec --skip-git-repo-check --sandbox read-only. The reviewer had no tools on this VM (it cannot run commands here): the prompt held the PR diff, CEFTabContentView+PaneMotion.swift in full, the CEFTabContentView part of CEFHostView.swift, and every remaining use of pageMotionHold.

Round 1 verdict, verbatim: VERDICT: SHIP / no findings.

[blacksmith-sh]

Found 10 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmph8xug7sn/summary-fail.json (live):/summary-fail.json (live):	View Logs
/tmp/tmpkg1np6rq/summary-missing.json (live):/summary-missing.json (live):	View Logs
[new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows/ [new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows	View Logs
[new_workspaces] the window draws no frames/[new_workspaces] the window draws no frames	View Logs
[tabs] debug.tab_switch timed 0 of 40 switches/ [tabs] debug.tab_switch timed 0 of 40 switches	View Logs
[tabs] the window draws no frames/[tabs] the window draws no frames	View Logs
imported web bundle inputs are not routed:/imported web bundle inputs are not routed:	View Logs
nightly cmux-tui resolve/nightly cmux-tui resolve	View Logs
nightly.yml must not read vars.NIGHTLY_SIGN while nightly-sign.yml is in shadow mode/ nightly.yml must not read vars.NIGHTLY_SIGN while nightly-sign.yml is in shadow mode	View Logs
the short nightly decide gate must use the pooled Linux route with a Blacksmith fallbac k/ the short nightly decide gate must use the pooled Linux route with a Blacksmith fallbac k	View Logs

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