src/vs/workbench/contrib/notebook/browser/view/cellParts/cellDnd.ts/CellDragAndDropController/getCellRangeAroundDragTarget
class CellDragAndDropController:	private getCellRangeAroundDragTarget(draggedCellIndex: number) {
		const selections = this.notebookEditor.getSelections();
		const modelRanges = expandCellRangesWithHiddenCells(this.notebookEditor, selections);
		const nearestRange = modelRanges.find(range => range.start <= draggedCellIndex && draggedCellIndex < range.end);

		if (nearestRange) {
			return nearestRange;
		} else {
			return { start: draggedCellIndex, end: draggedCellIndex + 1 };
		}
	}