Fix #2651: Grid Repeat Options has a Preview checkbox

The grid options' public page lists a Preview option: the repeat on the canvas follows the fields while the dialog is open. Object > Repeat > Options had none, so a change showed only after OK. Now a Grid Repeat's dialog has the checkbox: Cancel puts the original back without a history step, OK keeps the previewed values as one undo step. Radial and Mirror Repeat Options are left as they are, since their public pages list no Preview.

docs/gaps.md

@@ -1,6 +1,6 @@
 # Gaps
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-31 · **Change:** minor (G8: a gradient mesh from a file is budgeted at about a million patches and quads, #3592; estimate unchanged; previously: G13: gradient presets done; G1: Average & Join with a corner or smooth choice, Cmd+Alt+Shift+J, done; estimate unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-31 · **Change:** minor (G1: Grid Repeat Options has a Preview checkbox, #2651; scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
 
 ## Feature submission evidence
 
@@ -94,6 +94,7 @@ from G14 and the budget run of G15: **~170–270 h** one agent, ~50–80 h wall
 - **Done:** the Properties panel has the additional contextual controls of the public Properties panel overview: Blend Options in Quick Actions for one blend with the Blend tool, Merge Live Paint for a Live Paint group selected with more paths to merge (Live Paint Make and Merge refuse type, images and other objects that aren't paths, which used to vanish among the group's sources), the Width Profile list in Appearance with the Width tool or a variable-width stroke, an applied effect's Delete icon beside fx (with several effects it opens the Appearance panel), and Corner and Corner Radius for corners selected with Direct Selection (public doc cited in target-app-parity.md). Broader G1 estimates unchanged.
 - **Done (#2691):** a selected Grid Repeat ([public page](https://helpx.adobe.com/illustrator/desktop/paint-and-fill/create-and-edit-patterns/set-grid-repeat-options.html)) shows a handle below the grid, one right of it and one past its bottom-right corner: dragging them adds or removes rows, columns or both (1 to 500). A slider between the first two columns and one between the first two rows set the horizontal and vertical spacing, staying halfway across the gap under the pointer. Each drag is one undo step through `object.repeat.options` and Escape cancels it; the controls hide with the edges or the bounding box, and bounding-box handles keep priority where they meet. Radial Repeat handles remain. Estimates unchanged.
 
+- **Done (#2651):** Object › Repeat › Options… for a Grid Repeat has a Preview checkbox ([public page](https://helpx.adobe.com/illustrator/desktop/paint-and-fill/create-and-edit-patterns/set-grid-repeat-options.html)): while it is on the repeat on the canvas follows the fields, Cancel puts the original back without a history step and OK keeps the previewed values as one undo step. Radial and Mirror Repeat Options have none, as their public pages list none. Estimate unchanged.
 - **Done (#2877):** a selected Mirror Repeat shows its axis: drag the line or the center handle to move it, an end handle to rotate it (Shift: 45°); each drag is one undo step and Escape cancels it. Bounding-box handles take priority over the axis line; the center and end handles keep their actions. Broader G1 estimates unchanged.
 
 - **Existing-guide Escape cancellation:** Selection and Direct/Group Selection clear pending presses and cancel begun guide previews. App-input regressions cover preselected-guide document and interaction-start selection restoration, Undo/Redo and saved state, and later on-canvas motion/release. All eight app-input checks and the Direct Selection Escape control passed in current full CI; [Validation evidence](target-app-parity.md#evidence-what-ships-today-by-area). The broader G1 scope and estimate remain unchanged.
@@ -677,6 +678,7 @@ trap, and the defaults (0.25 pt, 100%, 40%) are VectorCraft's own, the pages giv
 | 2026-10-26 | minor | G9: EPS save-back: an opened EPS saves back to its own path as EPS, keeping the chosen artboard's page frame and transparent margins and the complete editable VectorCraft document; Save's TIFF preview is capped at 1024 px (Export keeps 2048); partly read, preview-only or damaged-editing-data sources still need confirmation before they are overwritten. This narrows G9's save-back workflow only; its import-fidelity items (layer and group structure, guides, open speed, live objects) and estimate are unchanged, and writing Illustrator's own editing data stays out of scope (#868) |
 | 2026-10-26 | minor | G7: View › New View… / Edit Views… ([public source](https://helpx.adobe.com/illustrator/using/viewing-artwork.html)): the View menu lists every one of a document's 25 saved views (it listed 10), Edit Views… lists them to rename or delete in one undo step (`view.saved.edit {edits}`), and a file's views are checked when it opens; New View/Edit Views leave G7's missing list; estimate unchanged |
 | 2026-10-25 | minor | G4: a double-click on a threaded port with the Selection tool breaks the thread there (`text.thread.break {id, port}`): the story flows into the frames before the break, the frames after it are left empty and stay threaded with each other when two or more; a double-click on a port with no thread does nothing; estimate unchanged |
+| 2026-10-31 | minor | G1: Grid Repeat Options has a Preview checkbox (#2651); estimate unchanged. |
 | 2026-10-25 | minor | G1: a selected Grid Repeat shows handles: the one below the grid adds or removes rows, the one right of it columns, the one past its bottom-right corner both, and the sliders between the first two columns and rows set the horizontal and vertical spacing; each drag is one undo step and Escape cancels it (#2691); bounding-box handles keep priority where they meet; Radial Repeat handles remain; estimates unchanged. |
 | 2026-10-25 | minor | Floating panels open in OS windows of their own on the desktop (inside the window on the web and on Wayland); saved layouts from earlier versions convert to the shared docking layout (#4135); scores and estimates unchanged (estimated) |
 | 2026-10-24 | minor | Recolor Artwork › Assign: double-clicking a row's new color opens the Color Picker over the dialog; its OK sets the row's new color in the model it was picked in (a CMYK mix stays CMYK, RGB becomes CMYK in a CMYK document), Cancel leaves the row as it was. A Lab new color is kept, but a Lab color can't be typed yet: the picker's Lab fields work in RGB, as for fill and stroke (part of #4028; Lab entry, swatch libraries and the row menu remain). Scores and estimates unchanged. |