fix(files): let a mouse wheel scroll CSV and XLSX previews horizontally

[waleedlatif1]

Summary

• Hovering a CSV/XLSX preview table and scrolling does nothing sideways on a mouse whose wheel reports only deltaY — the horizontal overflow is reachable only by dragging the scrollbar
• The zoomable previews (docx, pdf, pptx, image) already bind bindPreviewWheelZoom, whose horizontal branch maps a trackpad's deltaX, and Shift+deltaY on a plain mouse, onto scrollLeft. The tabular previews never bound anything
• Extracted that branch into bindPreviewHorizontalWheel — sharing the delta logic with the zooming variant rather than duplicating it — and bound it in all three tabular preview containers (csv-table-preview, xlsx-preview, preview-panel's CsvPreview) via a useHorizontalWheelScroll ref callback
• The new binder ignores ctrl/cmd+wheel, so browser page zoom still works over a table. These previews have no zoom of their own, unlike the zoomable ones

Latent until #6550: while the table was sized to the frame it never overflowed, so there was nothing to scroll. Independent of that PR though — the binder no-ops when scrollWidth <= clientWidth, so it is inert until the table is actually wider.

Type of Change

• Bug fix

Testing

8 unit tests in preview-wheel-zoom.test.ts covering trackpad deltaX, Shift+wheel, plain vertical wheel (must stay vertical), ctrl/cmd passthrough, the no-overflow no-op, unbind, and capture from a child cell. Mutation-verified: 3 fail when the binder body is removed.

jsdom does no layout, so the tests assert the handler's contract rather than real scrolling. Verified actual behavior separately with trusted wheel events in headless Chromium, hovering a table cell:

	plain wheel	Shift+wheel
unbound (today)	scrolls down 200	scrolls down 200 — no horizontal movement
bound (this PR)	scrolls down 200	scrolls right 200

Not yet exercised in the running app.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Aug 11, 2026 11:00pm

[cursor]

PR Summary

Low Risk
UI-only wheel gesture handling for file previews. Low risk overall, with a small shared-path change in bindPreviewWheelZoom that also affects zoomable previews.

Overview
Enables horizontal mouse-wheel scrolling on wide CSV and XLSX table previews, so Shift+wheel (and trackpad deltaX) can reach overflow without dragging the scrollbar.

Extracts shared horizontal-wheel handling into bindPreviewHorizontalWheel (also reused by bindPreviewWheelZoom), including line/page delta conversion and preserving vertical movement on diagonal pans. Wires it into the three tabular preview containers via a new useHorizontalWheelScroll ref hook, while leaving ctrl/cmd+wheel to the browser for page zoom.

^{Reviewed by Cursor Bugbot for commit f987a15. Configure here.}

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

[greptile-apps]

Greptile Summary

The PR adds horizontal wheel handling to CSV and XLSX preview containers while preserving native vertical scrolling and browser zoom behavior.

• Extracts shared horizontal-wheel handling from the zoomable-preview binder.
• Normalizes line- and page-mode wheel deltas before applying them to scroll offsets.
• Adds a callback-ref hook and binds it to all three tabular preview containers.
• Adds focused tests for gesture handling, delta conversion, passthrough behavior, overflow checks, child-event capture, and cleanup.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-wheel-zoom.ts	Extracts shared horizontal-wheel handling and correctly converts wheel delta units before updating scroll offsets.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/use-horizontal-wheel-scroll.ts	Adds a stable callback-ref hook that binds and cleans up the horizontal wheel listener with the preview node lifecycle.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-wheel-zoom.test.ts	Covers horizontal, shifted, diagonal, modifier-key, overflow, delta-mode, child-capture, and unbinding behavior.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/csv-table-preview.tsx	Attaches the horizontal-wheel callback ref to the CSV table’s scroll container using the required absolute import.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx	Attaches the horizontal-wheel callback ref to the inline CSV preview’s scroll container using the required absolute import.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/xlsx-preview.tsx	Attaches the horizontal-wheel callback ref to the XLSX table’s scroll container using the required absolute import.

_{Reviews (3): Last reviewed commit: "fix(files): normalize wheel deltas to pi..." | Re-trigger Greptile}

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

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^{Reviewed by Cursor Bugbot for commit f987a15. Configure here.}