[Table] Support dragging content from a selected table cell range

[juliaroldi]

Summary

Adds support for dragging content out of a selected table cell range. When the user presses down inside an existing table selection with a single click, the selection is converted into a native range selection so the highlighted content can be dragged and dropped elsewhere, gated behind the HandleDropInternalContent experimental feature.

Experimental Feature enabled:

Experimental Feature disabled:

Key changes:

• SelectionPlugin: detect mouse-down inside an active table selection (isInsideTableSelection) and switch to a draggable native range (setTableDragSelection), clearing the grey table-cell highlight and restoring the caret. On drop (via ChangeSource.Drop) or mouse-up, the temporary selection is cleared.
• DragAndDropPlugin: gate handleDroppedInternalContent behind the HandleDropInternalContent experimental feature and show a thin caret-like drag image when dragging from a table selection (adjustDraggingCursor).
• Export DOM_SELECTION_CSS_KEY and HIDE_CURSOR_CSS_KEY as @internal so the selection plugin can reset those editor styles while dragging.

How to test

1. Run the unit tests:
   • yarn test:fast --testPathPattern=SelectionPluginTest
   • yarn test:fast --testPathPattern=DragAndDropPluginTest
2. Manual test (requires the HandleDropInternalContent experimental feature enabled):
   • Select a range of table cells so the grey table selection appears.
   • Press and hold inside the selection with a single click, then drag to another location and drop.
   • Before this change: the table selection is cleared immediately on mouse-down and the content cannot be dragged.
   • After this change: the highlighted content stays draggable, a thin caret drag image follows the cursor, and dropping moves the content; the temporary selection is cleared on drop/mouse-up.

[github-actions]

PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-08-03 18:16 UTC