src/vs/workbench/contrib/notebook/browser/viewModel/notebookViewModelImpl.ts/NotebookViewModel/restoreEditorViewState
class NotebookViewModel:	restoreEditorViewState(viewState: INotebookEditorViewState | undefined): void {
		if (!viewState) {
			return;
		}

		this._viewCells.forEach((cell, index) => {
			const isEditing = viewState.editingCells && viewState.editingCells[index];
			const editorViewState = viewState.editorViewStates && viewState.editorViewStates[index];

			cell.updateEditState(isEditing ? CellEditState.Editing : CellEditState.Preview, 'viewState');
			const cellHeight = viewState.cellTotalHeights ? viewState.cellTotalHeights[index] : undefined;
			cell.restoreEditorViewState(editorViewState, cellHeight);
			if (viewState.collapsedInputCells && viewState.collapsedInputCells[index]) {
				cell.isInputCollapsed = true;
			}
			if (viewState.collapsedOutputCells && viewState.collapsedOutputCells[index] && cell instanceof CodeCellViewModel) {
				cell.isOutputCollapsed = true;
			}
		});
	}