     
     private let backOverlayView: UIView = {
         let backOverlayView = UIView(frame: CGRectZero)
-        backOverlayView.backgroundColor = UIColor(white: 0.0, alpha: 0.16)
+        backOverlayView.backgroundColor = UIColor(white: 0.0, alpha: 0.1)
         backOverlayView.alpha = 1.0
         return backOverlayView
         }()

    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        var dropShadowFrame = self.dropShadowView.frame
        dropShadowFrame.origin.x = 0 - dropShadowFrame.size.width
        dropShadowFrame.origin.y = 0
        dropShadowFrame.size.height = self.bounds.size.height
        self.dropShadowView.frame = dropShadowFrame
        self.addSubview(self.dropShadowView)
        
        self.clipsToBounds = false
        self.backgroundColor = UIColor.clearColor()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

        toView.transform = CGAffineTransformMakeTranslation(-maxOffset, 0)
        
        let backOverlayView = UIView(frame: containerBounds)
        backOverlayView.alpha = 1.0
        
        container.addSubview(toView)
        container.addSubview(backOverlayView)
