/// <summary>
/// Method used to add elements to the Document Container.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void AddElement_Click(object sender, RoutedEventArgs e)
{
RichTextBox rtb = new RichTextBox();
rtb.VerticalScrollBarVisibility = ScrollBarVisibility.Auto;
DocumentContainer.SetHeader(rtb, "New Window" + i.ToString());
Rect re = new Rect(30, 30, 300, 300);
DocumentContainer.SetMDIBounds(rtb, re);
DocContainer.Items.Add(rtb);
DocContainer.ActiveDocument = rtb;
i++;
}