src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/updateCellFocusMode
class NotebookEditorWidget:	updateCellFocusMode() {
		const activeCell = this.getActiveCell();

		if (activeCell?.focusMode === CellFocusMode.Output && !this._webviewFocused) {
			// output previously has focus, but now it's blurred.
			activeCell.focusMode = CellFocusMode.Container;
		}
	}