fix(layout-bridge): defer table fragment click mapping to geometry fallback

[tupizz]

Summary

This PR contains three fixes for table interaction in the layout engine:

1. Fix cursor placement in table cells (SD-1788)

Problem: Clicking on table cell padding, borders, or areas where elementsFromPoint doesn't return a line element caused the cursor to land in the wrong column.

Root cause: clickToPositionDom in dom-mapping.ts used processFragment for table fragments even when no line was in the hit chain. processFragment searches all lines across all cells using only Y-coordinate matching, so it picks the first cell with a matching Y — which is often the wrong column.

Fix: Added a guard that returns null for table fragments without a line in the hit chain, deferring to the geometry fallback (hitTestTableFragment) which correctly uses both X and Y coordinates to resolve the target cell.

File: packages/layout-engine/layout-bridge/src/dom-mapping.ts

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2. Fix table resize handles overflowing on split tables

Problem: When a table splits across page boundaries, the column resize handles (blue vertical lines) extended far beyond the table fragment — overflowing into the page gap and neighboring content below.

Root cause: In renderTableFragment.ts, the data-table-boundaries segment computation iterated over all rows in the table block (0 to rowCount), but each fragment only renders a subset of rows (fromRow to toRow + optional repeated headers). This caused every fragment to get segments with the full table's height.

Fix: Changed the segment computation to build a renderedRows list that mirrors the exact row rendering logic.

File: packages/layout-engine/painters/dom/src/table/renderTableFragment.ts

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3. Fix table cell click on page 2+ (geometry fallback coordinate fix)

Problem: Clicking in empty space below text in a table cell worked on page 1 but failed on page 2+. The cursor either didn't appear or landed in the wrong position.

Root cause: Two issues compounding:

1. Snap-to-nearest picks wrong target: When clicking empty table cell space (below text lines), the DOM-based mapping returns null. The geometry fallback's snap-to-nearest logic then picks a nearby paragraph instead of letting hitTestTableFragment handle the click.

2. Coordinate double-subtraction on page 2+: normalizeClientPoint adjusts Y by the page's DOM offset (pageOffsetY), making containerPoint page-relative. On page 1 this offset is ~0, but on page 2+ it's significant. Then clickToPosition subtracts pageTopY again, producing incorrect negative coordinates that cause hitTestPage to find the wrong page and hitTestTableFragment to fail entirely.

Fix:

• Skip snap-to-nearest when the click is within a table fragment's bounds (let hitTestTableFragment handle it)
• When DOM info is available, determine the page directly from elementsFromPoint (same technique normalizeClientPoint uses) and treat containerPoint as already page-relative, avoiding the double subtraction

File: packages/layout-engine/layout-bridge/src/index.ts

Test plan

• Added unit tests for table fragment click fallback behavior
• Added unit test for split-table segment scoping
• Added unit tests for table cell empty space clicks (page 1)
• Added unit tests for table cell clicks on page 2 (multi-page geometry path)
• All 1205 layout-bridge tests pass
• All 9105 tests pass across the monorepo
• Manual: verify cursor placement in table cells on page 1 and page 2+
• Manual: verify clicking below text in a table cell places cursor correctly
• Manual: open advanced-tables.docx, verify resize handles stay within each fragment

[linear]

SD-1788 Bug: Cursor Cannot be Reliably Placed in Table Cell

[Copilot]

Pull request overview

This PR fixes incorrect cursor placement in table cells by ensuring DOM-based click mapping defers to geometry-based table hit-testing when a click lands on a table fragment but doesn’t directly hit a .superdoc-line element (e.g., padding/borders where elementsFromPoint omits the line).

Changes:

• Update clickToPositionDom to return null for table fragments when no line is present in the hit chain, allowing clickToPosition to fall back to hitTestTableFragment.
• Add unit tests covering the “table fragment without line hit” deferral behavior.
• Add a table-related test intended to cover the “line is hit” path (but it currently doesn’t exercise that branch in JSDOM—see comments).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
packages/layout-engine/layout-bridge/src/dom-mapping.ts	Defers table fragment clicks without direct line hits to geometry fallback by returning null.
packages/layout-engine/layout-bridge/test/dom-mapping.test.ts	Adds tests for table fragment fallback behavior when elementsFromPoint omits line elements.

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[caio-pizzol]

Hey @tupizz! This is great.

I added a few comments, mainly regarding maintainability and cleanness of the codebase.

And also in this case, I would advise creating interaction stories here as well - since this happens specific on custom table through cursor positioning

[tupizz]

@caio-pizzol I'll be adding the visual testing

[caio-pizzol]

feel free to merge after interaction stories are added

great job!

[harbournick]

LGTM

[superdoc-bot]

🎉 This PR is included in superdoc v1.12.0-next.14

The release is available on GitHub release

[harbournick]

🎉 This PR is included in superdoc v1.12.0

The release is available on GitHub release

[superdoc-bot]

🎉 This PR is included in superdoc-cli v0.2.0

The release is available on GitHub release