---
id: S05
parent: M015
milestone: M015
provides:
  - AdminDropdown hover-to-open on desktop
requires:
  []
affects:
  []
key_files:
  - frontend/src/components/AdminDropdown.tsx
key_decisions:
  - Used useRef for matchMedia and leave timer to avoid re-renders on breakpoint changes
patterns_established:
  - (none)
observability_surfaces:
  - none
drill_down_paths:
  - .gsd/milestones/M015/slices/S05/tasks/T01-SUMMARY.md
duration: ""
verification_result: passed
completed_at: 2026-04-03T04:41:53.613Z
blocker_discovered: false
---

# S05: Admin Dropdown Hover on Desktop

**AdminDropdown opens on hover at desktop widths (≥769px) with a 150ms leave delay; mobile retains tap-to-toggle.**

## What Happened

Single-task slice. Added onMouseEnter/onMouseLeave handlers to AdminDropdown.tsx, guarded by a matchMedia('(min-width: 769px)') ref so hover only fires on desktop viewports. On mouseleave, a 150ms setTimeout bridges the CSS gap between trigger button and dropdown menu. The matchMedia listener updates the desktop flag dynamically on resize. Existing behavior (click-to-toggle, Escape close, outside-click close) remains intact. No CSS changes needed — existing absolute positioning already handles the layout at all breakpoints.

## Verification

Frontend build (npm run build) passes with zero errors and zero warnings. TypeScript compilation and Vite bundling complete in ~1s.

## Requirements Advanced

- R036 — Validated — hover opens dropdown on desktop, tap on mobile

## Requirements Validated

- R036 — AdminDropdown.tsx implements matchMedia guard + hover handlers + 150ms leave delay. Build passes.

## New Requirements Surfaced

None.

## Requirements Invalidated or Re-scoped

None.

## Deviations

None.

## Known Limitations

None.

## Follow-ups

None.

## Files Created/Modified

- `frontend/src/components/AdminDropdown.tsx` — Added matchMedia desktop guard, onMouseEnter/onMouseLeave with 150ms leave delay, useRef for timer cleanup
