 	///The indicator's color
 	var color: UIColor
 	///The indicator's top constraint
-	var topConstraint: NSLayoutConstraint?
+	var topConstraint = NSLayoutConstraint()
 	///The indicator's horizontal constraint
 	var horizontalConstraint = NSLayoutConstraint()
 	///The icon's view

							   attribute: .height, relatedBy: .equal,
							   toItem: nil, attribute: .notAnAttribute,
							   multiplier: 1, constant: frame.size.height),
			topConstraintItem,
			horizontalConstraint
			])
		topConstraint = topConstraintItem
	}

	///Create the horizontal constraint

	///- Parameter index: The selection index of the menu, where the indicator will appear
	///- Parameter heightForRow: The height of each menu item
	func moveTo(index: Int, heightForRow: CGFloat) {
		topConstraint.constant = (CGFloat(index) * heightForRow) + ((heightForRow - frame.size.height) / 2.0)
	}

	///:nodoc:
