/// <summary>
    /// This is the method that responds to the MouseLeftButtonDownEvent event.
    /// </summary>
    /// <param name="e"></param>
    protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
    {
        // We should process only the direct events in case TabItem is the selected one
        // otherwise we are getting this event when we click on TabItem content because it is in the logical subtree
        if (e.Source == this || !IsSelected)
        {
            if (SetFocus())
                e.Handled = true;
        }
        base.OnMouseLeftButtonDown(e);
    }