Clamp Settings window away from display edge

[lawrencecchen]

Summary

• clamp the Settings window to the visible display with an 18 px inset when it is configured or focused
• disable Settings window restoration so stale edge placements do not reopen flush against the display
• remove the dead traffic-light reframe path that was still caching and reapplying button frames with a zero offset

Verification

• ./scripts/reload.sh --tag setwin
• Reproduced on cmux-macmini by forcing Settings to X=0,Y=30, then verified the patched setmm build moves it to X=18,Y=48 when Settings is opened again

---

Summary by cubic

Clamp the Settings window to the visible screen with an 18px inset and disable restoration to prevent reopening flush against the display. Also remove the unused traffic-light reframe path that was reapplying zero-offset button frames.

• Bug Fixes

  • Clamp on configure and when showing to keep the window inside the screen’s visible area.
  • Set isRestorable = false to avoid restoring stale edge positions.

• Refactors

  • Remove traffic-light offset logic and cached base frames from WindowDecorationsController.

^{Written for commit 7c1da75. Summary will update on new commits.}

Summary by CodeRabbit

Bug Fixes

• Settings window now clamps to and remains within the visible screen area when opened or refocused, preventing it from appearing off-screen.
• Window decoration (traffic-light) buttons no longer shift position unexpectedly; their visibility is updated without repositioning, keeping window controls stable.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	May 2, 2026 10:20am
cmux-staging	Building	Preview, Comment	May 2, 2026 10:20am

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 554f041d-1f00-4715-b284-77f7f3c45cde

📥 Commits

Reviewing files that changed from the base of the PR and between 5319a72 and 7c1da75.

📒 Files selected for processing (1)

• Sources/cmuxApp.swift

---

📝 Walkthrough

Walkthrough

Removes per-window traffic-light button repositioning and related state; adds clamping to keep the Settings window origin inside the active screen's visibleFrame with an 18pt inset, applied during configure and focus.

Changes

Traffic-Light Button Repositioning Cleanup

Layer / File(s)	Summary
State Removal Sources/WindowDecorationsController.swift	Removed trafficLightBaseFrames dictionary tracking per-window button base frames.
Implementation Cleanup Sources/WindowDecorationsController.swift	Deleted applyTrafficLightOffset(...), applyTrafficLightOffsetNow(...), and trafficLightOffset(for:) stub.
Behavior Update Sources/WindowDecorationsController.swift	apply(to:) no longer applies positional offsets; it only calls hideStandardButtons(...) to update visibility.

Settings Window Visible Area Clamping

Layer / File(s)	Summary
Configuration Sources/cmuxApp.swift	Added visibleAreaInset: CGFloat = 18 constant to define padding from screen visible bounds.
Window Setup Sources/cmuxApp.swift	SettingsWindowPresenter.configure(window:) now calls clampToVisibleAreaIfNeeded(window) after setting minimum sizes.
Focus / Presentation Sources/cmuxApp.swift	SettingsWindowPresenter.focus(_:) calls clampToVisibleAreaIfNeeded(window) after deminiaturizing and before activating/ordering the window.
Core Clamping Logic Sources/cmuxApp.swift	Added clampToVisibleAreaIfNeeded(_:) which computes a clamped origin from the screen's visibleFrame inset by visibleAreaInset and updates the window frame only if the origin changes.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Add settings sidebar shell #3244: Modifies the same Settings window presentation and window-decoration handling code paths.

Poem

A rabbit nudges buttons out of sight,
Erases offsets, sets the window right,
With eighteen points it tucks the pane in tight,
Now Settings stays where screens are bright. 🐇

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% 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	The title 'Clamp Settings window away from display edge' accurately and specifically summarizes the main change—adding boundary clamping to the Settings window.
Description check	✅ Passed	The description covers the summary, verification details, and testing approach. However, it lacks a demo video (noted as optional in template) and the checklist section is missing, though most critical content is present.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat-settings-traffic-lights-offset

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Review rate limit: 6/8 reviews remaining, refill in 11 minutes and 18 seconds.}

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[greptile-apps]

Greptile Summary

This PR clamps the Settings window inside the visible display area (18 px inset) on both initial configuration and every re-focus, disables window restoration to prevent stale off-screen positions from persisting across launches, and removes the dead traffic-light offset code path that was caching button frames only to reapply a zero offset.

The clamping logic correctly guards against nil screens, handles windows wider than the available area, and is a no-op when the window is already in-bounds.

Confidence Score: 5/5

Safe to merge — changes are well-scoped, logic is correct, and dead code removal has no behavioral impact.

No P0 or P1 issues found. The clamping arithmetic is sound, nil-screen fallback is handled, and the isRestorable = false placement is correct. The only edge case (clamping a window whose frame has not yet been placed on first configure) is benign because the guard on clampedOrigin != frame.origin makes it a no-op when the frame is already valid.

No files require special attention.

Important Files Changed

Filename	Overview
Sources/WindowDecorationsController.swift	Removes dead-code traffic-light offset machinery: the cached base-frame dictionary, the async apply helper, and the trafficLightOffset(for:) stub that always returned .zero. No behavior change.
Sources/cmuxApp.swift	Adds clampToVisibleAreaIfNeeded to both configure(window:) and focus(_:), sets isRestorable = false to prevent stale positions. Clamping logic handles narrow windows and nil-screen fallback correctly; minor edge case around clamping before a window has been placed on first configure.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[show] --> B{existingWindow?}
    B -- No --> C[openWindow]
    C --> D[configure window]
    D --> E[isRestorable = false]
    E --> F[clampToVisibleAreaIfNeeded]
    B -- Yes --> N[focus window]
    N --> O{isMiniaturized?}
    O -- Yes --> P[deminiaturize]
    P --> F
    O -- No --> F
    F --> G{screen available?}
    G -- nil --> H[fallback NSScreen.main]
    G -- present --> I[use window.screen]
    H --> J[compute clamped origin]
    I --> J
    J --> K{origin changed?}
    K -- No --> L[no-op]
    K -- Yes --> M[setFrame display true]
    M --> Q[makeKeyAndOrderFront]
    L --> Q

Loading

_{Reviews (1): Last reviewed commit: "Clamp Settings window away from display ..." | Re-trigger Greptile}