 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 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, thumbnailsEnabled: Bool = true) -> 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

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

        }
    }
    
    /// Whether or not the thumbnails bar should be enabled
    fileprivate var isThumbnailsEnabled = true {
        didSet {
            if thumbnailCollectionControllerHeight == nil {
                _ = view
            }
            if !isThumbnailsEnabled {
                thumbnailCollectionControllerHeight.constant = 0
            }
        }
