             }, completion: { finished in
                 self.isAnimating = false
             })
+            
+            let shadowAnim = CABasicAnimation(keyPath: "shadowPath")
+            shadowAnim.duration = 0.3
+            shadowAnim.fromValue = thumbView.layer.shadowPath
+            shadowAnim.toValue = UIBezierPath(roundedRect: thumbView.bounds, cornerRadius: thumbView.layer.cornerRadius).cgPath
+            thumbView.layer.add(shadowAnim, forKey: "shadowPath")
+            thumbView.layer.shadowPath = UIBezierPath(roundedRect: thumbView.bounds, cornerRadius: thumbView.layer.cornerRadius).cgPath
         }
         else {
             if (self.isTracking) {

            }, completion: { finished in
                self.isAnimating = false
            })
        }
        else {
            if self.isTracking {

                self.isAnimating = false
        })
        
        let shadowAnim = CABasicAnimation(keyPath: "shadowPath")
        shadowAnim.duration = 0.3
        shadowAnim.fromValue = thumbView.layer.shadowPath
        shadowAnim.toValue = UIBezierPath(roundedRect: thumbView.bounds, cornerRadius: thumbView.layer.cornerRadius).cgPath
        thumbView.layer.add(shadowAnim, forKey: "shadowPath")
        thumbView.layer.shadowPath = UIBezierPath(roundedRect: thumbView.bounds, cornerRadius: thumbView.layer.cornerRadius).cgPath
        
        return true
    }
    
