Cell annotations

Attach a short note (≤ 280 chars) to any body cell. Notes paint a persistent corner marker, persist per-document to localStorage, stay glued to their source cell across sort/filter, and are listed origin-wide in a cross-document popup. No runtime dependencies; works fully offline.

Try it

1. Annotate: hover (or Tab to) a body cell, click the ✎ pin, type a note, and click Save. A blue corner triangle marks the cell; its text is wired to the cell via aria-describedby.
2. Persists: reload the page — the marker and note come back from localStorage (key gs:<url>:annotations).
3. Follows its cell: click GS, then the sort lozenge on Q3 revenue — rows reorder but the note stays on its original region's row.
4. Cross-document: once a note exists on the origin, a Show annotations button appears bottom-right. It lists every note across same-origin documents (try the two linked reports below) with dates, and deep-links to each cell.

Sample table

Cross-document

Two more same-origin pages. Annotate a cell on each, then open Show annotations from any of them to jump between documents.