XLSX: form controls (control properties, <controls> and VML ClientData), alongside kept controls

Buttons, scroll bars (sliders) and spin buttons are written the three
ways the published formats describe: a control properties part
(xl/ctrlProps/ctrlPropN.xml, formControlPr with objectType, fmlaLink,
min, max, inc, page, val and horiz), a <control> in the sheet's
<controls> inside mc:AlternateContent with its anchor, print and locked
flags and a button's macro="[0]!Name", and a VML shape with
x:ClientData. Notes and controls share one VML drawing per sheet; shape
ids come from 1024-id blocks listed in the drawing's idmap (after the
blocks kept header and footer drawings use), notes first, so each
control's shapeId names its VML shape.

Reading prefers the properties part, takes the caption from the VML
text box and falls back to the VML alone for files that only have it.
Values are clamped to whole numbers 0..30000 and repaired to pass the
model's rules.

Form controls of other kinds (check boxes, list boxes, drop-downs) stay
with pass-through: the reader returns the shape numbers it modelled,
and pass-through keeps the rest of the <controls> element and VML
drawing without them. On save, modelled controls join the kept
<controls> element and take a fresh shape block in the kept drawing, so
a sheet with both round-trips without duplicates. Properties part names
are reserved so kept parts of other sheets don't collide with them.

Button actions xlsx has no place for (commands, fixed inputs, output
cells) travel in a chunked hidden name keyed by sheet and position, and
are taken back out on open. The streaming sheet parser now splits only
shallow <row> elements, so an anchor's <xdr:row> inside <controls> stays
in the tree.

docs/file-format-parity.md

@@ -1,6 +1,6 @@
 # File-format parity
 
-> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-26 · **Change:** minor (`file.exportCsv {values: true}` writes raw values for automation; .xls dialog sheets are skipped instead of read as worksheets; `.xls` import reads each sheet's display options from WINDOW2: right-to-left, gridlines, headings, zeros, formulas; XLSX text boxes and shapes keep their paragraphs' right-to-left direction on save; CSV/TSV/TXT can open with every field kept as text via `file.open {csvAsText}`; formulas over Excel's 8,192 characters, and `%` or call chains past the nesting limit, are parse errors instead of stack overflows when a file is opened; XLSX PivotTables read and write `rowGrandTotals`/`colGrandTotals` the way Excel does, so a table saved with only one grand total opens with the right one; HTML export keeps right-to-left; CSV and text import detects likely Windows-1256 Arabic when invalid UTF-8 has Arabic byte runs; other invalid UTF-8 remains Windows-1252; HTML export places pictures and charts, as inline SVG, at their anchors) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
+> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-31 · **Change:** minor (form controls: buttons, scroll bars and spin buttons read and written) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
 
 Every format Excel opens or saves, with GridCraft's read and write support, fidelity and tests.
 Part of [target-app-parity.md](target-app-parity.md). **File formats: ~50% ready, 80–120 h**
@@ -41,7 +41,7 @@ values) is still dropped.
 
 | Format | Excel | GridCraft read | GridCraft write | Fidelity / notes | Tests |
 |---|---|---|---|---|---|
-| `.xlsx` Excel Workbook (transitional) | R/W, native | yes | yes | Cells, shared/array/dynamic formulas, shared strings (with their Japanese phonetic runs — ふりがな — kept through open + save: `<rPh>` offsets and readings and `<phoneticPr>` are written back next to the same string; the table holds each text once, so duplicate `<si>` items whose text is the same but whose readings differ keep only the first reading, with a warning on open), styles, themes, merges, CF, validation, tables, comments and notes, hyperlinks, names, freeze panes, outline, print settings, pictures, shapes, charts (simplified, see [chart-parity.md](chart-parity.md)), sparklines, PivotTables (caches and tables), protection, calc settings, show objects (`workbookPr showObjects`). **Kept unchanged on save (pass-through, `passthrough.rs`):** custom document properties, ribbon customisation and add-in task panes, custom XML, links to external workbooks (never followed or refreshed), data connections, sheet query tables, printer settings (#324), form controls, ActiveX controls, OLE objects and sheet backgrounds (with their VML shapes), and chart sheets (#727: the sheet, drawing, chart, style and colour parts are written back unchanged in their place, and left out when a sheet they plot was deleted or renamed or a worksheet took their name; they can't be edited or created); dropped when their sheet is deleted or their parts point at content GridCraft rewrites. **Not preserved:** slicers and slicer caches, timelines, data model, query tables attached to tables, sheet and workbook `extLst` entries we don't model, chart details; Strict Open XML files keep nothing. Never checked in Excel across a corpus: repair prompts unknown. 100 MB files fail (#175) A picture used on several sheets is written once (#985). | `roundtrip.rs`, `fixtures.rs`, `malformed.rs`, `pivot_tests.rs` |
+| `.xlsx` Excel Workbook (transitional) | R/W, native | yes | yes | Cells, shared/array/dynamic formulas, shared strings (with their Japanese phonetic runs — ふりがな — kept through open + save: `<rPh>` offsets and readings and `<phoneticPr>` are written back next to the same string; the table holds each text once, so duplicate `<si>` items whose text is the same but whose readings differ keep only the first reading, with a warning on open), styles, themes, merges, CF, validation, tables, comments and notes, hyperlinks, names, freeze panes, outline, print settings, pictures, shapes, charts (simplified, see [chart-parity.md](chart-parity.md)), sparklines, PivotTables (caches and tables), form controls (buttons, scroll bars and spin buttons: control properties parts, `<controls>` and VML `x:ClientData`; a VML-only control is read too), protection, calc settings, show objects (`workbookPr showObjects`). **Kept unchanged on save (pass-through, `passthrough.rs`):** custom document properties, ribbon customisation and add-in task panes, custom XML, links to external workbooks (never followed or refreshed), data connections, sheet query tables, printer settings (#324), other form controls (check boxes, list boxes, drop-downs; written in the same `<controls>` element and VML drawing as the modelled ones), ActiveX controls, OLE objects and sheet backgrounds (with their VML shapes), and chart sheets (#727: the sheet, drawing, chart, style and colour parts are written back unchanged in their place, and left out when a sheet they plot was deleted or renamed or a worksheet took their name; they can't be edited or created); dropped when their sheet is deleted or their parts point at content GridCraft rewrites. **Not preserved:** slicers and slicer caches, timelines, data model, query tables attached to tables, sheet and workbook `extLst` entries we don't model, chart details; Strict Open XML files keep nothing. Never checked in Excel across a corpus: repair prompts unknown. 100 MB files fail (#175) A picture used on several sheets is written once (#985). | `roundtrip.rs`, `fixtures.rs`, `malformed.rs`, `pivot_tests.rs` |
 | `.xlsx` Excel Workbook (transitional) | R/W, native | yes | yes | Cells, shared/array/dynamic formulas, shared strings (with their Japanese phonetic runs — ふりがな — kept through open + save: `<rPh>` offsets and readings and `<phoneticPr>` are written back next to the same string; the table holds each text once, so duplicate `<si>` items whose text is the same but whose readings differ keep only the first reading, with a warning on open), styles, themes, merges, CF, validation, tables, notes (with their shown/hidden state) and threaded comments with replies, resolved state and timestamps (`threadedComments` and `persons` parts, #300), hyperlinks, names, freeze panes, outline, print settings, pictures, shapes, charts (simplified, see [chart-parity.md](chart-parity.md)), sparklines, PivotTables (caches and tables), protection, calc settings, show objects (`workbookPr showObjects`). **Not preserved:** unmodelled parts and extensions (form controls, slicer caches, timelines, external links, OLE objects, custom XML, data model, query tables, chart details). Never checked in Excel across a corpus: repair prompts unknown. 100 MB files fail (#175) A picture used on several sheets is written once (#985). | `roundtrip.rs`, `fixtures.rs`, `malformed.rs`, `pivot_tests.rs` |
 | `.xlsx` Excel Workbook (transitional) | R/W, native | yes | yes | Cells, shared/array/dynamic formulas, shared strings (with their Japanese phonetic runs — ふりがな — kept through open + save: `<rPh>` offsets and readings and `<phoneticPr>` are written back next to the same string; the table holds each text once, so duplicate `<si>` items whose text is the same but whose readings differ keep only the first reading, with a warning on open), styles, themes, merges, CF, validation, tables, comments and notes, hyperlinks, names, freeze panes, outline, print settings, pictures, shapes, charts (simplified, see [chart-parity.md](chart-parity.md)), sparklines, PivotTables (caches and tables), protection, Allow Edit Ranges (`protectedRanges` with their password hashes, #307), calc settings, show objects (`workbookPr showObjects`). **Not preserved:** unmodelled parts and extensions (form controls, slicer caches, timelines, external links, OLE objects, custom XML, data model, query tables, chart details). Never checked in Excel across a corpus: repair prompts unknown. 100 MB files fail (#175) A picture used on several sheets is written once (#985). | `roundtrip.rs`, `fixtures.rs`, `malformed.rs`, `pivot_tests.rs` |
 | `.xlsx` Excel Workbook (transitional) | R/W, native | yes | yes | Cells, shared/array/dynamic formulas, styles, themes (the major/minor `latin`, East Asian `ea` and complex-script `cs` typefaces and the per-script `<a:font script>` lists are kept through a save), merges, CF, validation, tables, comments and notes, hyperlinks, names, freeze panes, outline, print settings, pictures, shapes, charts (simplified, see [chart-parity.md](chart-parity.md)), sparklines, PivotTables (caches and tables), protection, calc settings. **Kept unchanged on save (pass-through, `passthrough.rs`):** custom document properties, ribbon customisation and add-in task panes, custom XML, links to external workbooks (never followed or refreshed), data connections, sheet query tables, printer settings (#324), form controls, ActiveX controls, OLE objects and sheet backgrounds (with their VML shapes), pictures in headers and footers (`&G`, #1257: their VML drawing and images are written back unchanged; they are not shown, and can't be inserted), and chart sheets (#727: the sheet, drawing, chart, style and colour parts are written back unchanged in their place, and left out when a sheet they plot was deleted or renamed or a worksheet took their name; they can't be edited or created); dropped when their sheet is deleted or their parts point at content GridCraft rewrites. **Not preserved:** slicers and slicer caches, timelines, data model, query tables attached to tables, sheet and workbook `extLst` entries we don't model, chart details; Strict Open XML files keep nothing. Never checked in Excel across a corpus: repair prompts unknown. 100 MB files fail (#175) | `roundtrip.rs`, `fixtures.rs`, `malformed.rs`, `pivot_tests.rs` |