The event-trace inspector in each demo keyed its `{#each}` by a
`Date.now()` timestamp (`entry.at` / `h.at`). A single interaction can
stamp `data-event` on several elements within the same millisecond, so
two trace entries share the key and Svelte throws `each_key_duplicate`
(reported on dropdown-menu).
The trace is an ephemeral, 3-item, text-only log with no transitions or
stateful children, so positional reconciliation is correct: drop the
timestamp key (the each becomes unkeyed). The `fmtTime(...at)` display is
left intact.
Swept all 22 demos carrying the pattern (21 keyed by `entry.at` + announce
by `h.at`): dropdown-menu, context-menu, menubar, navigation-menu, listbox,
grid-list, table, tree-view, tree-grid, feed, command, carousel, drag-drop,
clipboard, announce, alert-dialog, button, color-field, link-preview,
range-calendar, time-field, time-range-field.
Verified: `as \w+ (\w+.at)` -> 0 occurrences site-wide; `npm run check`
0 errors; browser repro on dropdown-menu + table (burst of events, no
each_key_duplicate, console clean).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
dev