 
     // actions
     fileprivate var activityViewController: UIActivityViewController!
-    fileprivate var panGesture: UIPanGestureRecognizer!
+    fileprivate var panGesture: UIPanGestureRecognizer?
 
     // for status check property
     fileprivate var isEndAnimationByToolBar: Bool = true

    
    open func prepareForClosePhotoBrowser() {
        cancelControlHiding()
        view.removeGestureRecognizer(panGesture)
        NSObject.cancelPreviousPerformRequests(withTarget: self)
    }
    

            return
        }
        panGesture = UIPanGestureRecognizer(target: self, action: #selector(SKPhotoBrowser.panGestureRecognized(_:)))
        panGesture?.minimumNumberOfTouches = 1
        panGesture?.maximumNumberOfTouches = 1

        if let panGesture = panGesture {
            view.addGestureRecognizer(panGesture)
        }
    }
    
    func configureActionView() {
