/// <summary>
        /// when change tab item reload the others- to get "clean" data
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void UpdateTabItem_GotFocus(object sender, RoutedEventArgs e)
        {
            this.AddTabItem.Content = null;
            AddContractUserControl a = new AddContractUserControl();

            this.AddTabItem.Content = a;

            this.RemoveTabItem.Content = null;
            RemoveContractUserControl r = new RemoveContractUserControl();

            this.RemoveTabItem.Content = r;
        }
        /// <summary>
        /// when change tab item reload the others- to get "clean" data
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void AddTabItem_GotFocus(object sender, RoutedEventArgs e)
        {
            this.RemoveTabItem.Content = null;
            RemoveContractUserControl r = new RemoveContractUserControl();

            this.RemoveTabItem.Content = r;

            this.UpdateTabItem.Content = null;
            UpdateContractUserControl u = new UpdateContractUserControl();

            this.UpdateTabItem.Content = u;
        }