src/vs/workbench/contrib/notebook/browser/view/cellParts/cellFocus.ts/CellFocusPart/constructor
class CellFocusPart:	constructor(
		containerElement: HTMLElement,
		focusSinkElement: HTMLElement | undefined,
		notebookEditor: INotebookEditor
	) {
		super();

		this._register(DOM.addDisposableListener(containerElement, DOM.EventType.FOCUS, () => {
			if (this.currentCell) {
				notebookEditor.focusElement(this.currentCell);
			}
		}, true));

		if (focusSinkElement) {
			this._register(DOM.addDisposableListener(focusSinkElement, DOM.EventType.FOCUS, () => {
				if (this.currentCell && (this.currentCell as CodeCellViewModel).outputsViewModels.length) {
					notebookEditor.focusNotebookCell(this.currentCell, 'output');
				}
			}));
		}
	}