gridcraft/docs/gaps.md

# Gaps

> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-11-02 · **Change:** minor (§17: equations; earlier: §13: Solver Sensitivity report; earlier: §4: chart resizing is no longer a gap; earlier: §13: Analysis ToolPak has all 19 tools; earlier: §4: chart data tables implemented with XLSX round-trip and print/PDF; earlier: §13: Solver Options; earlier: §13: Solver Load/Save Model and Reset All) · **Target:** Microsoft Excel (Microsoft 365)

Every known shortfall against Excel, one entry each, ranked by user impact (what blocks someone
using GridCraft for real work first). This is the work list: pick from the top, check the open
PRs first (50 open on 2026-10-10; several already address entries here), and update the entry
when you land work. Estimates are Opus 5.5 agent-hours. Area detail lives in the linked parity
docs; the summary is in [target-app-parity.md](target-app-parity.md).

Kinds: **F** feature · **U** UI/UX · **FF** file format · **H** hardware · **L** localization ·
**P** performance · **S** stability.

## Beta blockers

No alpha blockers: every core workflow passes the [alpha gate](roadmap.md#alpha-gate).


### 1. XLSX output not proven in Excel or on real files (FF)
- **Missing:** a run over a real-world XLSX corpus, and confirmation that Excel opens what we save
  with no repair prompt (PivotTables, charts, CF, validation, dynamic arrays, tables).
- **Evidence:** round-trip tests cover our own files only (`crates/xlsx/src/tests/`); PivotTable
  round-trip noted as "unverified in real Excel" since 10-07; #64 (dynamic-array flag) shows the
  class of bug.
- **Impact:** the main format; a repair prompt or silent loss destroys trust.
- **Estimate:** 15–25 h, plus owner time in Excel. [file-format-parity.md](file-format-parity.md)

### 2. Large workbooks don't open; recalc is single-threaded (P, H)
- **Missing:** streaming read for ~100 MB XLSX; multi-threaded recalc; 100k-dependent edit under
  100 ms (was ~0.4 s); whole-sheet operations bounded.
- **Evidence:** #175; no threading in `crates/calc`; PR #152 (whole-sheet Fill/Remove Duplicates
  out of memory), PR #151 (current region past 10,000 rows).
- **Impact:** finance and data users routinely have big workbooks.
- **Estimate:** 25–40 h. [target-app-parity.md](target-app-parity.md#performance), [hardware-parity.md](hardware-parity.md)

### 3. Some unmodelled XLSX content is dropped on save (FF)
- **Missing:** slicers and their caches, timelines, the data model, query tables attached to
  tables, unmodelled `extLst` entries, chart details. Pass-through (#330) keeps custom XML,
  external links, connections, sheet query tables, printer settings, form and ActiveX controls,
  OLE objects and sheet backgrounds; never checked in Excel (repair prompts unknown).
- **Evidence:** `crates/xlsx/src/passthrough.rs` (what is kept, and why the rest isn't).
- **Impact:** open-edit-save still simplifies workbooks with slicers, timelines or Power Pivot.
- **Estimate:** 6–10 h. [file-format-parity.md](file-format-parity.md)

### 4. Charts lose options on round trip; shallow chart model (F, FF)
- **Missing:** axis scaling, label options, error bars, per-point formatting.
- **Added:** data tables beneath column, bar, line, area and compatible combo charts, with legend keys, border controls, live source values, native XLSX round-trip and print/PDF.
- **Evidence:** `Chart` holds only title, legend position, two flags and axis titles
  (`crates/model/src/features.rs`); all 2-D kinds survive XLSX round trip (#158, #161); charts
  resize from eight handles (#190). Smooth lines (#62), Switch Row/Column (#116) and trendlines
  (read, written, drawn) landed. Multi-level category axes (year beside month) are read, drawn
  and written back.
- **Impact:** charts are in most business workbooks.
- **Estimate:** 25–35 h for beta (40–60 h full). [chart-parity.md](chart-parity.md)

### 5. Text in non-Latin scripts doesn't render or export (L)
- **Missing:** cross-platform script coverage, Devanagari/Thai shaping verification, non-Latin PDF and Arabic UI layout.
- **Evidence:** system-font fallback for CJK, Thai and Hebrew landed in #38 (closed #32); #142
  (Chinese text) awaits confirmation; #54 (symbols as boxes on Fedora). Arabic shared shaping/bidi,
  editing and cell Context/LTR/RTL now have focused regressions and full gates. Arabic font
  delivery and PDF output are separate PRs; other script shaping still needs verification.
- **Missing:** CJK font fallback, complex shaping (Arabic, Devanagari, Thai), bidi, non-Latin PDF.
- **Evidence:** system-font fallback for CJK, Thai and Hebrew landed in #38 (closed #32), and for
  Arabic (system, fontconfig and craft-fonts faces); a UI font with Arabic of its own (DejaVu Sans
  in the Flatpak) still draws interface Arabic ahead of fontconfig's choice (#229); #142
  (Chinese text) awaits confirmation; #54 (symbols as boxes on Fedora); no shaping for Arabic or
  Devanagari; PDF writer uses 14 standard fonts only.
- **Impact:** blocks most of the world's users even with an English UI.
- **Estimate:** 12–20 h. [localization-parity.md](localization-parity.md)

### 6. Calculation correctness bugs (F)
- **Missing:** nothing known. The four this entry tracked have landed: 15-significant-digit
  equality (#57, so `=0.1+0.2=0.3` is TRUE and MATCH and COUNTIF agree), spill updates after
  structural edits and cleared blockers (#133, #139; PRs #148, #157), 3-D span deletion (#140),
  and qualified names after a sheet rename (#134). Iterative calculation for circular references
  landed too, with its settings in File › Options › Formulas.
- **Impact:** wrong numbers are worse than missing features, so this entry is kept until the
  oracle suite of §15 can say the category is clear rather than only these five reports being so.
- **Estimate:** — [function-parity.md](function-parity.md#formula-language)

### 7. Legacy `.xls` only partly read; encrypted workbooks can't be saved with a password (FF)
- **Evidence:** #121: Excel 97-2003 (BIFF8) `.xls` files now open (values, formulas, number
  formats, merges, sizes, names, and cell formatting: fonts, fills, borders, alignment); exact theme colours (XFExt), charts, pictures, comments, conditional
  formats, validation and BIFF5 files are not read, and `.xls` is never written. Password-encrypted
  `.xlsx` workbooks (Agile and Standard encryption) open with their password since #11, but are
  saved without it: GridCraft can't write an encrypted file yet. Encrypted `.xls` (FILEPASS) and
  RC4-encrypted files are still refused with a message.
- **Impact:** common in finance, government and anything older than 2007; encrypted files are
  routine in business.
- **Estimate:** 14–21 h (`.xls` objects 10–15, encryption 4–6). [file-format-parity.md](file-format-parity.md)

### 8. PivotTables: no slicers, calculated items, PivotCharts; unverified in Excel (F)
- **Evidence:** `parity-checklist.md` missing `insert.slicer`, `insert.timeline`,
  `insert.pivotChart`, `table.insertSlicer`; calculated items and GETPIVOTDATA missing (calculated fields
  and values on rows done). Show Details (double-click a value, subtotal or grand total cell) lists
  its source records on a new sheet. The "Enable show details" option (`pivot.options`
  `enableShowDetails`, saved as `enableDrill`) turns it off; it has no PivotTable Options dialog
  yet (command only).
- **Impact:** pivots are the analyst's main tool.
- **Estimate:** 20–30 h for beta (25–40 h full).

### 9. Keyboard-first users: key tips, shortcuts, context menus (U)
- Next/previous sheet navigation now skips Hidden and VeryHidden worksheets without activating a
  hidden sheet at the workbook boundary. Other keyboard gaps below remain.
- **Evidence:** #33, #49 (key tips: initial Home-tab support landed in #43 on 10-10, the rest of the ribbon not yet), #110, #28 (selection),
  59 command shortcuts vs Excel's 200+.
- **Estimate:** 12–20 h. [ui-parity.md](ui-parity.md)

### 10. Crashes and freezes reported from the field (S)
- **Evidence:** #120 (Intel UHD crash on Windows), #117 (error on close, macOS), #166 (freeze opening
  from Finder; PRs #164, #167), #76 (flashing on Windows 11), #130 (caught panic in table styles).
- **Estimate:** 8–12 h plus an autosave/recovery soak.

## After beta

### 11. No localization at all (L)
- Catalog: ribbon-only in five languages (#31, #104, #82; ~12% of strings each), and 943 strings
  (~43%) in Japanese (10-17) and Brazilian Portuguese, including the dialog labels, messages, File
  view and menus. The remaining dialogs, menus and messages are English; en-US function names and
  separators (#45); German in PR #163. **Estimate:**
  100–165 h including #5. [localization-parity.md](localization-parity.md)

### 12. Get & Transform, external data, data model (F)
- No Power Query editor, connections, refresh, From Web/database/folder sources, relationships or
  data model (`data.fromWeb`, `data.relationships` missing). **Estimate:** 60–100 h.

### 13. Analysis tools: Solver, Analysis ToolPak, Forecast Sheet (F)
- Forecast Sheet (`data.forecastSheet`) and the FORECAST.ETS family are in, including Forecast
  Start (hindcast, #785).
- Solver (`data.solver`, #327) has Simplex LP with integer/binary branch and bound, a local
  nonlinear method (augmented Lagrangian, not GRG), the Evolutionary method, and Answer,
  Sensitivity and Limits reports. Report refusal leaves the solution, saved model and history unchanged; a
  successful solve and its reports share one Undo step (#1050). Load/Save Model writes the
  model on cells of its sheet and reads it back; Reset All removes it. Solver Options sets the
  evaluation limit, Integer Optimality and the Evolutionary options, which are saved with the
  model. AllDifferent constraints and the Population report remain.
- The Analysis ToolPak (`data.analysisToolPak`) has all 19 of Excel's tools; their chart output
  remains. **Estimate:** 12–20 h.

### 14. Page Layout view and print polish (U, F)
- Page Layout view landed (#329): paper view with rulers and in-place header/footer editing.
  Margins are dragged on the rulers (#792). Remaining: pictures in headers/footers, Different First Page / Odd & Even pages. Desktop now submits directly through craft-print with printer choice, copies, duplex and grayscale; browser printing stays available. Print ranges and driver tray/options UI remain. **Estimate:** 5–10 h.

### 15. Remaining functions and an oracle suite (F)
- 18 missing, 9 stubs; no Excel-computed oracle corpus; #137, #138. **Estimate:** 16–26 h.
- 20 missing, 9 stubs; no Excel-computed oracle corpus; #137, #138. **Estimate:** 17–29 h.
- 21 missing, 9 stubs; no Excel-computed oracle corpus; #137, #138. **Estimate:** 18–30 h.
- 18 missing, 9 stubs; no Excel-computed oracle corpus; #137, #138. **Estimate:** 18–30 h.
  [function-parity.md](function-parity.md)

### 16. Collaboration and review (F)
- No co-authoring, Show Changes, comment navigation, notes ↔ comments
  conversion; cloud storage requested (#86). **Estimate:** 35–55 h (co-authoring scope needs the owner).

### 17. Insert objects (F)
- Ink strokes now survive XLSX save/reopen as editable polylines. Inserted icons still lose their
  identity/artwork on save (#551); native Office InkML import is not implemented.
- SmartArt, WordArt, signature line, objects, 3-D models, screenshot; 8 shape kinds vs ~170;
  pictures in cells (#61, PR #105). Equations exist (LaTeX source with a live preview, Office Math in xlsx); there is
  no structured (WYSIWYG) equation editing and no ink equations. **Estimate:** 25–40 h.

### 18. Accessibility (U)
- AccessKit on, but no accessible grid/ribbon tree, no high contrast, no checker. **Estimate:** 12–18 h.
  [ui-parity.md](ui-parity.md#accessibility)

### 19. XLSB/ODS beyond values; minor formats (FF)
- XLSB and ODS import values only, no write; no `.prn`, `.dif`, XML Spreadsheet 2003 (`.slk` imports values, formulas, number formats and widths); CSV
  writes raw instead of displayed values; templates saved with the workbook content type.
  **Estimate:** 15–23 h.

### 20. Multiple windows; pen pressure (H)
- Desktop windows done: a native window per workbook window, New Window on the same workbook,
  Switch Windows, Arrange All. Left: Arrange All across monitors, one window on the web, no
  pressure or tilt in ink. **Estimate:** 5–8 h.
  [hardware-parity.md](hardware-parity.md)

### 21. Automation and add-ins (F)
- VBA out of scope (dropped on open, #6); no Office Scripts compatibility; no plugin or custom
  function API. **Estimate:** 25–40 h plus an owner decision.

### 22. AI features (F)
- No in-app assistant, natural-language formulas or Analyze Data; agent control via MCP is
  already strong. **Estimate:** 30–50 h; model choice needs the owner.

### 23. Mobile (platform)
- No iOS, iPadOS or Android layout. **Estimate:** 30–60 h.

### 24. Fonts and look (U)
- Font weights beyond regular/bold (#168), system font list (#4), Calibri metrics (#29), macOS
  chrome (#169, #170), Linux title bar (#54), icon consistency across apps (#173). **Estimate:** 7–12 h.

## Revision history

| Date | Change | Summary |
|---|---|---|
| 2026-11-02 | minor | §17: equations (Insert › Equation, LaTeX source, gallery, editor) |
| 2026-11-02 | minor | §13: Solver Sensitivity report: shadow prices, reduced costs and allowable ranges for Simplex LP; Lagrange multipliers and reduced gradients for GRG Nonlinear |
| 2026-11-02 | minor | §4: charts, like every floating object, move and resize from eight handles (#190), so resizing is no longer listed as missing; the evidence is one paragraph again, without the stale "PRs #158, #161 open" |
| 2026-11-01 | minor | §13: the Analysis ToolPak has all 19 of Excel's tools (two-factor Anova with and without replication, z-Test, Fourier Analysis, Random Number Generation, Sampling); its chart output remains. The stale "`data.solver`, `data.analysisToolPak` missing" and "no Forecast Start" sentences removed |
| 2026-11-01 | minor | §4: chart data tables implemented for column, bar, line, area and compatible combo charts, with legend keys and border settings, live source values, XLSX round-trip and print/PDF; other chart gaps remain. |
| 2026-10-31 | minor | §13: Solver Options (Max Evaluations, Integer Optimality and the Evolutionary options), saved with the model |
| 2026-10-31 | minor | §13: Solver Load/Save Model (`data.solverSaveModel`, `data.solverLoadModel`) and Reset All (`data.solverReset`), with buttons in the Solver Parameters dialog |
| 2026-10-26 | minor | Arabic shared bidi display/editing and persisted cell reading direction; other script and PDF work remain separate |
| 2026-10-26 | minor | §5: Arabic text renders in cells and the interface: a system Arabic face (Tahoma, Arial or Segoe UI on Windows, Geeza Pro on macOS, Noto Sans or Naskh Arabic on Linux) joins the script fallbacks, fontconfig's Arabic choice, when it has Arabic letters, leads the Arabic fallbacks and draws Arabic wherever the UI or cell font has none, such as the default cell fonts (part of #229; a UI font with Arabic of its own, such as DejaVu Sans in the Flatpak, still draws interface Arabic, left for a follow-up), and craft-fonts' Noto Sans Arabic is a required face allowed on the web. Workbook fonts without Arabic keep every script fallback. Shaping and bidirectional layout remain separate work |
| 2026-10-24 | minor | §8: PivotTable Enable show details: `pivot.options` `enableShowDetails` turns Show Details off for a PivotTable, read and written in XLSX as `enableDrill` |
| 2026-10-23 | minor | §8: PivotTable Show Details: double-clicking a value cell lists its source records on a new sheet (#2364) |
| 2026-10-22 | minor | §20: a native window per workbook window, New Window on the same workbook and Arrange All on the desktop; left: Arrange All across monitors, the web's one window, pen pressure (estimate 10–14 h → 5–8 h) |
| 2026-10-20 | minor | §11: the Japanese catalog covers the dialogs, messages and menus — 943 keys (~43%), matching the pt-BR coverage; a test keeps the two catalogs in step |
| 2026-10-17 | minor | §6: the five reports it tracked are closed and their PRs merged (#57, #133, #139, #140, #134; PRs #148, #155, #156, #157); the entry stays open for §15's oracle suite |
| 2026-10-15 | minor | §6: Maximum Iterations and Maximum Change in File › Options › Formulas; dropped the stale "no Options dialog yet" |
| 2026-10-15 | minor | §13: Solver prepares reports before committing the solution, model and report sheets together; report refusal preserves the workbook and Undo/Redo (#1050) |
| 2026-10-13 | trivial | §4: multi-level category axes landed |
| 2026-10-12 | minor | §9: next/previous sheet commands retain the current visible sheet and selection when there is no visible destination |
| 2026-10-12 | minor | rows auto-fit oversized fonts on open and whole-row/column formatting (#833) |
| 2026-10-12 | minor | Page Layout view: dragging margins on the rulers (#792) removed from the §14 remainder |
| 2026-10-12 | minor | §13: Forecast Sheet Forecast Start (hindcast) landed (#785) |
| 2026-10-12 | minor | §17: ink geometry survives XLSX saves; the icon portion of #551 remains |
| 2026-10-12 | minor | §8: values on rows (Σ Values in Rows, `dataOnRows`) laid out, moved and round-tripped |
| 2026-10-12 | minor | Desktop File > Print now discovers printers and submits PDF jobs through pinned craft-print with printer choice, copies, duplex and grayscale; browser printing and PDF export remain available. Remaining print parity includes page ranges and driver-specific tray/options UI; physical printer fidelity needs hardware validation. |
| 2026-10-11 | minor | §6: iterative calculation for circular references landed (Maximum Iterations, Maximum Change) |
| 2026-10-11 | minor | §15: trim-reference operators (`A1:.E10`, `A1.:E10`, `A1.:.E10`) parse and evaluate |
| 2026-10-11 | minor | §4: trendlines (six types, forecast, equation and R²) read, written and drawn |
| 2026-10-11 | minor | §7: password-encrypted workbooks open with their password; saving with one remains (#11) |
| 2026-10-11 | minor | §16: comment navigation, Show Comments, Show All Notes and Convert to Comments landed (#281) |
| 2026-10-11 | minor | §7: `.xls` (BIFF8) import of values, formulas and number formats (#121) |
| 2026-10-11 | minor | §3: XLSX pass-through keeps custom XML, external links, connections, query tables, printer settings, controls and OLE objects (#330, #324) |
| 2026-10-11 | minor | §13: Forecast Sheet landed (#322) |
| 2026-10-11 | minor | §15: ODDFPRICE, ODDFYIELD, ODDLPRICE, ODDLYIELD added (18 functions missing) |
| 2026-10-11 | minor | §15: PERCENTOF and EUROCONVERT added (20 functions missing) |
| 2026-10-11 | minor | §15: BAHTTEXT added (21 functions missing) |
| 2026-10-11 | minor | §15: TRIMRANGE added (21 functions missing; trim-reference operators still missing) |
| 2026-10-11 | minor | §16: Allow Edit Ranges landed (#307) |
| 2026-10-11 | minor | §8: calculated fields added |
| 2026-10-11 | minor | §8: PivotCharts added |
| 2026-10-11 | minor | §13, §15: FORECAST.ETS family landed (#314) |
| 2026-10-10 | minor | Updated for the 10-10 merges (#17, #31, #38, #62, #82, #104, #116) and the new chart resize bug (#190) |
| 2026-10-10 | minor | Noted that no gap blocks the alpha gate |
| 2026-10-10 | major | Created: 24 ranked gaps with evidence, from the full re-measure and the 60 open issues |