         }
         
         controller.backButton = backButton
-        controller.thumbnailsEnabled = thumbnailsEnabled
+        controller.isThumbnailsEnabled = isThumbnailsEnabled
         
         if let actionButtonImage = actionButtonImage {
             controller.actionButton = UIBarButtonItem(image: actionButtonImage, style: .plain, target: controller, action: #selector(actionButtonPressed))

        }
    }
    
    /// Set this to `false` if you don't want to load the thumbnails strip.
    fileprivate var thumbnailsEnabled = true {
        didSet {
            if thumbnailCollectionControllerHeight == nil {
                _ = view
            }
            if !thumbnailsEnabled {
                thumbnailCollectionControllerHeight.constant = 0
            }
        }

extension PDFViewController {
    /// Initializes a new `PDFViewController`
    ///
    /// - parameter document:            PDF document to be displayed
    /// - parameter title:               title that displays on the navigation bar on the PDFViewController; 
    ///                                  if nil, uses document's filename
    /// - parameter actionButtonImage:   image of the action button; if nil, uses the default action system item image
    /// - parameter actionStyle:         sytle of the action button
    /// - parameter backButton:          button to override the default controller back button
    /// - parameter isThumbnailsEnabled: whether or not the thumbnails bar should be enabled
    ///
    /// - returns: a `PDFViewController`
    public class func createNew(with document: PDFDocument, title: String? = nil, actionButtonImage: UIImage? = nil, actionStyle: ActionStyle = .print, backButton: UIBarButtonItem? = nil, isThumbnailsEnabled: Bool = true) -> PDFViewController {
        let storyboard = UIStoryboard(name: "PDFReader", bundle: Bundle(for: PDFViewController.self))
        let controller = storyboard.instantiateInitialViewController() as! PDFViewController
        controller.document = document
