src/vs/workbench/contrib/notebook/browser/view/notebookCellList.ts/NotebookCellList/attachWebview
class NotebookCellList:	attachWebview(element: HTMLElement) {
		element.style.top = `-${NOTEBOOK_WEBVIEW_BOUNDARY}px`;
		this.rowsContainer.insertAdjacentElement('afterbegin', element);
		this._webviewElement = new FastDomNode<HTMLElement>(element);
	}