public void OnDurationChange()
    {
        float DurationTmp;

        if (!float.TryParse(Duration.text, out DurationTmp))
        {
            DurationImg.color = InvalidColor;
            return;
        }
        if (DurationTmp < 0.0001f)
        {
            DurationImg.color = InvalidColor;
            return;
        }
        DurationImg.color = ValidColor;
        OperationManager.SetHoldNoteDuration(OperationManager.SelectedHoldNote[0], DurationTmp);
    }