[teamleaderleo]

Leo: "and also the "unfoused" opacity shift is MILDLY jarring... i think it's actually ok but just make the opacity shift not as drastic"

Leo-ask: ask-35d63f0002 (opacity part)

Cause

An unfocused pane can be marked in three ways. In a default two-pane split only one of them draws:

• The veil over the pane (panes.inactiveDimming, theme token 0.10, already softened from 0.14 in cmux-next: unfocused panes dim subtly (a theme token) and ease over 150 ms #22948) draws only with layout dimming on, appearance.borders none with the border indicator, or ringless floating panes with the border indicator. The default appearance.focusIndicator is tabs, so it does not draw. Over a glass window (Leo's glass-clear) its fill is clear anyway.
• The Ghostty unfocused-split-opacity dim is off unless the user's Ghostty config sets it (cmux loads = 1 first).
• The unfocused pane's tab fade (ChromeEmphasis .fade, focus.inactiveTabStrength) does draw. cmux-next: an unfocused pane's tabs fade further, so the focused pane is plain to see #22987 raised it from 0.35 to 0.6 so the focused pane is easy to tell apart for Cmd-W. That made the shift on every focus change bigger.

Change

• focus.inactiveTabStrength default: 0.6 -> 0.4 (Debug tunable; the LayoutStyle literal matches). On a focus change, the selected pill of the unfocused pane now keeps 0.6 of its fill (was 0.4), and its labels mix 40% toward the page (was 60%). The contrast floors (3.5:1, 2.5:1, 2:1) and the 150 ms veil ease are unchanged.
• 0.4 is a compromise and not a straight halving to 0.3. It stays above the 0.35 that cmux-next: an unfocused pane's tabs fade further, so the focused pane is plain to see #22987 found too faint to show which pane Cmd-W closes. The tunable stays in Debug Settings (Focus > Unfocused tabs strength) for live tuning.
• FocusedPaneTabCueTests now checks both sides: the unfocused pill keeps between half and two thirds of the focused fill, so the cue stays visible and the shift is not drastic. The label check (fainter than 0.6 of the focused contrast, still above the floors) is unchanged.
• Docs: plans/cmux-next/focus.md, components/tabs.md, design-tokens.json/.md.

Changelog

Changed: In cmux NEXT, an unfocused pane's tabs fade less when focus moves to another pane.

Observed / Not run

• Fleet compile-check --app and FocusedPaneTabCueTests (fleet package-test lane) at the head: results are in a comment.
• No capture: a one-constant change to a Debug-tunable default. The new strength is checked by FocusedPaneTabCueTests on the tokens it produces, and Leo can compare values live with the Debug Settings slider.

Agent session: cosmic-gray

🤖 Generated with Claude Code

---

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---

Summary by cubic

Softens the dim on an unfocused pane's tabs so switching focus is less jarring, while keeping the cue readable.

The default focus.inactiveTabStrength drops from 0.6 to 0.4. 0.6 made the shift on every focus change too drastic; 0.35 was too faint to tell which pane Cmd-W would close. 0.4 keeps the selected pill at 0.6 of its focused fill. The contrast floors and the veil fade are unchanged, and the strength stays tunable in Debug Settings.

• Updates FocusedPaneTabCueTests to check both sides: the unfocused pill keeps between half and two thirds of the focused fill; the label fade check is unchanged.
• Updates the LayoutStyle literal and the focus/design-token docs, correcting per-style fade values and the hover fill formula (alpha × (1 − strength/2)) at strength 0.4.

^{Written for commit 0bd552f. 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 0bd552f: 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=pr23956 -f ref=fix/softer-unfocused-dim -f platform=macos -f backend_mode=local

red: cmux-next checks (god files, concurrency, crash safety, l10n); no finished base run on 4ae5de4 to compare; do not merge until green; see lane-rules

[blacksmith-sh]

Found 12 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmpcqr7y5bn/summary-missing.json (live):/summary-missing.json (live):	View Logs
/tmp/tmpqzdnt_l2/summary-fail.json (live):/summary-fail.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
convention violations found (ERROR lines above)./ convention violations found (ERROR lines above).	View Logs
nightly cmux-tui resolve/nightly cmux-tui resolve	View Logs
test_every_submodule_free_checkout_on_an_owned_runner_resets_submodules (main.Reuse dWorkspaceSubmodules.test_every_submodule_free_checkout_on_an_owned_runner_resets_submo dules)/ test_every_submodule_free_checkout_on_an_owned_runner_resets_submodules (main.Reuse dWorkspaceSubmodules.test_every_submodule_free_checkout_on_an_owned_runner_resets_submo dules)	View Logs
test_every_submodule_free_checkout_on_an_owned_runner_resets_submodules (main.Reuse dWorkspaceSubmodules.test_every_submodule_free_checkout_on_an_owned_runner_resets_submo dules) (job='web-bundles')/ test_every_submodule_free_checkout_on_an_owned_runner_resets_submodules (main.Reuse dWorkspaceSubmodules.test_every_submodule_free_checkout_on_an_owned_runner_resets_submo dules) (job='web-bundles')	View Logs

...and 2 more test failures. View all on Blacksmith

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[teamleaderleo]

cmux-next crash-class rules / cmux-next crash-class rules is red on 11 of 11 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[teamleaderleo]

Review (independent subagent): SHIP at 2af1116

• Reviewer confirmed that, by default, the shift a two-pane split shows is the unfocused pane's tab fade. The veil only draws with the border indicator, borders none or dimsInactivePanes, and the Ghostty dim is off unless the user's config sets it.
• The tunable default and the LayoutStyle literal agree. Nothing else pins 0.6. Reviewer checked numerically that FocusedPaneTabCueTests holds at 0.4 for all four test themes (pill 0.6x; label contrast 0.28 to 0.44 of focused). The docs table and formula now match the code.
• Fleet compile-check --app: passed at 4746fed and at 2af1116.
• Fleet FocusedPaneTabCueTests run (package-test lane) did not reach the tests: ensure-web-bundles fails on base because webviews/src/agent-session/acpmux/inspector/ContextSection.css (added in cmux NEXT Inspector: Context opens to Claude's breakdown; Connectors says N to reconnect #23789) is not listed in build-agent-pane-web.sh. That is a base red, not this PR's.
• Non-blocking finding, wrong before this PR too: the quiet row says the pill is transparent, but the code keeps 0.4 of its fill.

[teamleaderleo]

Bead cx-tk3ep created for this PR by the cmux coordinator.

[teamleaderleo]

Review (independent subagent): SHIP at 0bd552f

• This head is a merge of feat-cmux-next into 2af1116, to pick up the ci: the agent pane page ships the Inspector's ContextSection.css (base red since #23789) #23935 web-bundle fix. Against the new base the PR diff is byte-identical to the 7-file diff reviewed at 2af1116. No conflict was resolved, and nothing in the base update touches inactiveTabStrength or ChromeEmphasis.
• Fleet compile-check --app passed at this head. Fleet FocusedPaneTabCueTests passed 3/3 at this head.
• The red checks at this head come from files and jobs this PR does not touch, so they are base reds:
  • crash-class rules (selector super calls);
  • nightly-guards release-notary (restored-terminals-come-back.md highlight);
  • Guard status;
  • cmux-next checks: namespace-type errors in AttentionHighlightLook.swift and ChiefWorkspaceName.swift, and the job-structure test;
  • release rails.

[github-actions]

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.3973137732601 (15186f150b)
• cmux NEXT nightly 1.0.0-nightly.3973389583201 (48a69e9f66)