                 savedArticlesViewController.editController.navigationDelegate = nil
                 removeChild(savedArticlesViewController)
                 addChild(readingListsViewController)
-                leftButtonType = .add
                 scrollView = readingListsViewController?.collectionView
                 isSearchBarHidden = true
                 activeEditableCollection = readingListsViewController

    
    private var isSavedArticlesEmpty: Bool {
        return savedArticlesViewController.editController.isCollectionViewEmpty
    }
    
    private enum LeftButtonType {
        case add
        case none
    }
    
    private var leftButtonType: LeftButtonType = .none {
        didSet {
            guard oldValue != leftButtonType else {
                return
            }
            switch leftButtonType {
            case .add:
                navigationItem.leftBarButtonItems = [addReadingListBarButtonItem]
            default:
                navigationItem.leftBarButtonItems = []
            }
        }
    }

    private var isSearchBarHidden: Bool = false {

    }
    
    func didChangeEditingState(from oldEditingState: EditingState, to newEditingState: EditingState, rightBarButton: UIBarButtonItem?, leftBarButton: UIBarButtonItem?) {
        defer {
            navigationBar.updateNavigationItems()
        }
        navigationItem.rightBarButtonItem = rightBarButton
        navigationItem.rightBarButtonItem?.tintColor = theme.colors.link
        let editingStates: [EditingState] = [.swiping, .open, .editing]
        let isEditing = editingStates.contains(newEditingState)
        actionButton.isEnabled = !isEditing
        guard isEditing, searchBar.isFirstResponder else {
            return
        }
        searchBar.resignFirstResponder()
    }
    
    func newEditingState(for currentEditingState: EditingState, fromEditBarButtonWithSystemItem systemItem: UIBarButtonSystemItem) -> EditingState {
