fix: resolve event listener and timer cleanup leaks causing memory growth

[notJoon]

Summary

• useModalCloseEvent: Cleanup called addEventListener instead of removeEventListener, accumulating keydown listeners on every unmount
• SubMenuButton: Cleanup removed mouseover instead of mousemove, leaving dangling listeners on document across all pages
• useAutoDisconnect: Cleanup called clearTimeout on a setInterval ID, preventing the 10s background check internal from ever being cleared

Changes

useModalCloseEvent

Before	After
window.addEventListener("keydown", handleEsc) in cleanup	window.removeEventListener("keydown", handleEsc)
Handler functions recreated every render (stale closure)	Wrapped in useCallback with proper deps
useEffect deps: []	useEffect deps: [handleEsc, onClickOutbound]

SubMenuButton

Before	After
removeEventListener("mouseover", ...)	removeEventListener("mousemove", ...)

useAutoDisconnect

Before	After
clearTimeout(backgroundCheckIntervalRef.current)	clearInterval(backgroundCheckIntervalRef.current)

Performance Measurements

Tested by opening/closing a SelectBox dropdown 10 times and recording Chrome DevTools Performance for ~15 seconds.

Before (tested on beta.gnoswap.io)

After (tested on Vercel preview)

Results

Metric	Before	After	Change
Listeners	Staircase increase on every open/close	Stable after initial mount	Accumulation eliminated
JS Heap range	54.1 → 68.8 MB (+14.7 MB)	48.8 → 59.7 MB (+10.9 MB)	~26% less growth
Profiling overhead	85.6% of self time	46.9% of self time	Reduced listener dispatch overhead

Summary by CodeRabbit

• Bug Fixes
  • Corrected event listener cleanup in sub-menu interactions to properly remove registered listeners
  • Fixed timer cleanup to use the correct cancellation method
  • Improved modal close event handler stability and cleanup to prevent memory leaks and ensure proper event removal

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
gnoswap-interface	Building	Preview, Comment	Feb 25, 2026 8:30am

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 89fa8c4 and 7d0108a.

📒 Files selected for processing (3)

• packages/web/src/components/common/header/sub-menu-button/SubMenuButton.tsx
• packages/web/src/hooks/common/use-auto-disconnect.tsx
• packages/web/src/hooks/common/use-modal-close-event.tsx

---

Walkthrough

Three files fix event listener cleanup issues and improve hook dependency management. SubMenuButton corrects mouseover listener cleanup, use-auto-disconnect replaces clearTimeout with clearInterval, and use-modal-close-event introduces useCallback memoization and fixes listener cleanup logic.

Changes

Cohort / File(s)	Summary
Event Listener Cleanup Fixes packages/web/src/components/common/header/sub-menu-button/SubMenuButton.tsx, packages/web/src/hooks/common/use-auto-disconnect.tsx	SubMenuButton aligns cleanup to remove mousemove listener matching registered event. use-auto-disconnect corrects cleanup to use clearInterval instead of clearTimeout for interval timers.
Modal Close Event Hook Refactor packages/web/src/hooks/common/use-modal-close-event.tsx	Introduces useCallback for memoized event handlers (handleEsc, onClickOutbound). Updates useEffect dependency array to [handleEsc, onClickOutbound]. Corrects cleanup to remove both click and keydown listeners, fixing duplicate keydown listener issue.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 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 (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main objective: fixing event listener and timer cleanup leaks. All three changes in the PR address memory growth from improper cleanup, making the title directly relevant to the changeset.

_{✏️ 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 fix/event-listener-timer-leaks

---

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

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

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud