Disable titlebar page help tooltips

[lawrencecchen]

Summary

• stop installing AppKit .help() tooltips on transient titlebar page controls
• keep the new-page button accessible with an explicit accessibility label
• add a small guard test for the titlebar page tooltip policy

Testing

• xcodebuild -project GhosttyTabs.xcodeproj -scheme cmux-unit -destination 'platform=macOS' -only-testing:cmuxTests/TitlebarPageTooltipPolicyTests/testTitlebarPageControlsNeverInstallAppKitHelpTooltips test
• ./scripts/reload.sh --tag issue-1036-tooltip-tracking-uaf

Issues

• Closes Crash in NSToolTipManager: use-after-free on mouse-enter tracking area #1036

Context

Sentry issue CMUXTERM-MACOS-1X1 first appeared on 2026-02-28 in stable com.cmuxterm.app@0.61.0+73, so the grouped NSWindow.cmux_sendEvent tracking-area crash already existed. The nightly event in #1036 first appears in com.cmuxterm.app.nightly@0.61.0-nightly.20260307+2279003110001, and the most likely recent trigger is commit 4de975e6a4cc84fd099aa1673348617cafd0e50a from #1030, which added .help() tracking to the new titlebar page strip.

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Summary by cubic

Disable AppKit help tooltips on titlebar page controls to prevent tracking-area crashes during hover, drag, close, and selection changes. Keeps the New Page button accessible and adds a guard test.

• Bug Fixes
  • Gate help(...) behind ContentView.titlebarPageControlsShouldInstallHelpTooltips() which returns false.
  • Replace the New Page tooltip with an accessibilityLabel to preserve screen reader support.
  • Add TitlebarPageTooltipPolicyTests to enforce the no-tooltip policy.
  • Addresses Crash in NSToolTipManager: use-after-free on mouse-enter tracking area #1036 and Sentry CMUXTERM-MACOS-1X1.

^{Written for commit 54afe8f. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Disabled tooltips for titlebar page controls to improve user experience.

• Tests

  • Added test coverage for titlebar page control tooltip behavior.

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Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Mar 7, 2026 6:58am

[coderabbitai]

📝 Walkthrough

Walkthrough

A static method is added to ContentView that returns false to conditionally disable AppKit tooltips for titlebar page controls. The method is integrated into UI elements to prevent tooltip installation, with a corresponding test verifying the gating behavior.

Changes

Cohort / File(s)	Summary
Titlebar Tooltip Gating Sources/ContentView.swift	Added titlebarPageControlsShouldInstallHelpTooltips() static method returning false; conditionally gates .help() tooltip application in titlebar page button and new page button construction to disable AppKit tooltip registration.
Tooltip Policy Test cmuxTests/WorkspaceContentViewVisibilityTests.swift	Added TitlebarPageTooltipPolicyTests class with test asserting titlebarPageControlsShouldInstallHelpTooltips() returns false, ensuring transient titlebar page controls never register AppKit tooltips.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 No more tooltips dancing near,
When titlebar controls appear—
The mouse can roam without a fear,
Of tracking ghosts that used to linger here! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 14.29% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	Title clearly summarizes the main change: disabling AppKit help tooltips on titlebar page controls to fix the use-after-free crash.
Description check	✅ Passed	Description covers Summary (what and why), Testing (test command and reload script), and relevant metadata; matches template requirements well.
Linked Issues check	✅ Passed	Code changes fully implement the objective from issue #1036: disabling AppKit help tooltips to prevent use-after-free crashes, adding accessibility labels, and including guard tests.
Out of Scope Changes check	✅ Passed	All changes are narrowly scoped to the tooltip disabling feature and related test; no unrelated modifications detected outside PR objectives.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch issue-1036-tooltip-tracking-uaf

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@cmuxTests/WorkspaceContentViewVisibilityTests.swift`:
- Around line 93-100: The test currently only asserts the policy method
ContentView.titlebarPageControlsShouldInstallHelpTooltips() returns false;
instead, render a titlebar control at runtime (via a small test seam or
test-only factory such as adding a TestTitlebarControl or a
ContentView.makeTitlebarControlForTesting() that produces the actual control
used in the titlebar) and assert no AppKit help tooltip gets registered on the
rendered view (e.g., verify the view and its subviews have no toolTip/helpTag
set and that addToolTip/removeToolTip were not applied) so the test checks
observable behavior rather than the policy return value.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 920fd5c7-738c-4249-b903-fff63bf025f9

📥 Commits

Reviewing files that changed from the base of the PR and between 4de975e and 54afe8f.

📒 Files selected for processing (2)

• Sources/ContentView.swift
• cmuxTests/WorkspaceContentViewVisibilityTests.swift

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

This guards the helper, not the tooltip behavior.

Line 96 only asserts that the policy method currently returns false, so this still passes if a future titlebar control forgets to honor that policy and installs .help(...) anyway. Please test through a small runtime seam closer to the rendered control/configuration so the assertion covers “no AppKit help tooltip gets installed” rather than the helper’s literal return value. As per coding guidelines, "Do not add tests that only verify source code text, method signatures, AST fragments, or grep-style patterns; tests must verify observable runtime behavior" and "If a behavior cannot be exercised end-to-end yet, add a small runtime seam or harness first, then test through that seam rather than testing implementation details."

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@cmuxTests/WorkspaceContentViewVisibilityTests.swift` around lines 93 - 100,
The test currently only asserts the policy method
ContentView.titlebarPageControlsShouldInstallHelpTooltips() returns false;
instead, render a titlebar control at runtime (via a small test seam or
test-only factory such as adding a TestTitlebarControl or a
ContentView.makeTitlebarControlForTesting() that produces the actual control
used in the titlebar) and assert no AppKit help tooltip gets registered on the
rendered view (e.g., verify the view and its subviews have no toolTip/helpTag
set and that addToolTip/removeToolTip were not applied) so the test checks
observable behavior rather than the policy return value.

[greptile-apps]

Greptile Summary

This PR fixes a use-after-free crash (Sentry CMUXTERM-MACOS-1X1) caused by AppKit tooltip tracking areas being installed on transient titlebar page controls. The crash was introduced in PR #1030 when .help() modifiers were added to the new-page button and per-page tab buttons in ContentView.swift. The fix removes those .help() calls behind a static policy gate (titlebarPageControlsShouldInstallHelpTooltips() → always false) and preserves accessibility for the icon-only new-page button by substituting .accessibilityLabel. A guard test is added to prevent accidental re-enablement.

• Crash root cause addressed: .help() on short-lived SwiftUI views in the titlebar strip registers AppKit tooltip tracking areas that can be accessed after the view is destroyed during hover/drag/close/selection churn.
• Accessibility preserved: the new-page (+) button gains an explicit .accessibilityLabel("New Page"); per-page tab buttons still expose their title via the Text(page.title) child, so VoiceOver is unaffected.
• Policy gate pattern: the titlebarPageControlsShouldInstallHelpTooltips() static method and its corresponding test act as a regression guard, ensuring no one re-enables AppKit tooltips here without a crash-safe replacement in hand.

Confidence Score: 5/5

• This PR is safe to merge — it directly fixes a confirmed use-after-free crash with no functional regressions and includes a regression guard test.
• The change is minimal, targeted, and fixes a crash confirmed in production. The policy gate pattern and test prevent accidental re-enablement of the crashing behavior. Accessibility is preserved via explicit labels. No negative side effects or risk vectors identified.
• No files require special attention.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Render titlebar page strip] --> B{isTitlebarHovered?}
    B -- No --> C[Render page tabs only]
    B -- Yes --> D[Create newPageButton\nwith .accessibilityLabel]
    C --> E{titlebarPageControlsShouldInstallHelpTooltips?}
    D --> E
    E -- true\n never --> F[Apply .help tooltip\nAppKit tracking area registered]
    E -- false\n always --> G[Render button as-is\nNo AppKit tracking area]
    F --> H[Crash risk: UAF on\ntracking area during churn]
    G --> I[Safe: no tooltip\ntracking area installed]

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_{Last reviewed commit: 54afe8f}

[cubic-dev-ai]

No issues found across 2 files