     private var fractions : Array<TimeFraction> = Array()
     private let KVOStartedKey = "started"
     
-    override func layoutSubviews() {
+    override public func layoutSubviews() {
         let oldBounds : CGRect = bounds
         super.layoutSubviews()
         

    
    :returns: The position of the time fraction.
    */
    func positionOfTimeFraction(timeFraction : TimeFraction) -> Int? {
        return find(fractions, timeFraction)
    }
    
    /**
    Resets all time fractions.
    */
    func reset() {
        for fraction in fractions {
            fraction.reset()
        }

    
    :returns: True, if the insertion was successful.
    */
    public func insert(timeFraction : TimeFraction) -> Int? {
        timeFraction.addObserver(self, forKeyPath: KVOStartedKey, options: .New, context: nil)
        fractions.append(timeFraction)
        setNeedsLayout()
