Table Virtualization Scroll Stability Spec

Summary

Folded markdown tables should not cause sudden document height or scrollbar jumps when scrolling. CodeMirror should have a close table-widget height estimate before the widget is measured in the viewport.

Goals

• Keep the outer editor scroll height stable while documents with folded table previews are virtualized.
• Preserve the current folded table preview and touched-table source-editing behavior.
• Keep the estimate deterministic and derived from the same parsed table data used to render the preview.
• Cover the estimate with focused tests so future table style changes account for scroll stability.

Non-Goals

• Rich table editing.
• Horizontal table virtualization.
• Pixel-perfect prediction for every possible wrapped cell value.

Implementation Notes

• apps/desktop/src/components/editor-area/table-decorations.ts owns folded table widget rendering.
• CodeMirror WidgetType.estimatedHeight is the intended API for reserving space for unmeasured block widgets in the heightmap.
• The estimate should account for the table header, body rows, borders, and widget padding using the editor font-size default plus the table preview's own line-height/padding constants.

Acceptance Criteria

• Folded table widgets provide a positive estimated height before DOM measurement.
• The estimate grows with table row count.
• Existing folded/unfolded table behavior remains unchanged.
• Focused table decoration tests pass.