     
     private class func up(drop: Drop, after: Double, interval: NSTimeInterval) {
         drop.topConstraint.constant = drop.heightConstraint.constant
+        let options: UIViewAnimationOptions = .AllowUserInteraction | .CurveEaseIn
         UIView.animateWithDuration(
             interval,
             delay: after,
-            options: UIViewAnimationOptions.AllowUserInteraction | UIViewAnimationOptions.CurveEaseIn,
+            options: options,
             animations: { [weak drop] () -> Void in
                 if let drop = drop {
                     drop.layoutIfNeeded()

            } else {
                restartUpTimer(2.0)
                topConstraint.constant = 0.0
                UIView.animateWithDuration(
                    NSTimeInterval(0.1),
                    delay: NSTimeInterval(0.0),
                    options: UIViewAnimationOptions.AllowUserInteraction | UIViewAnimationOptions.CurveEaseOut,
                    animations: { [weak self] () -> Void in
                        if let s = self { s.layoutIfNeeded() }
                    }, completion: nil

            drop.updateHeight()
            
            drop.topConstraint.constant = 0.0
            let options: UIViewAnimationOptions = .AllowUserInteraction | .CurveEaseOut
            UIView.animateWithDuration(
                NSTimeInterval(0.25),
                delay: NSTimeInterval(0.0),
                options: options,
                animations: { [weak drop] () -> Void in
                    if let drop = drop { drop.layoutIfNeeded() }
                }, completion: nil
