src/vs/workbench/contrib/notebook/browser/contrib/cellStatusBar/notebookVisibleCellObserver.ts/NotebookVisibleCellObserver/_onModelChange
class NotebookVisibleCellObserver:	private _onModelChange() {
		this._viewModelDisposables.clear();
		if (this._notebookEditor.hasModel()) {
			this._viewModelDisposables.add(this._notebookEditor.onDidChangeViewCells(() => this.updateEverything()));
		}

		this.updateEverything();
	}