private void btnAddLineToEnd_Click(object sender, EventArgs e)
        {
            string line = this.txLine.Text;

            LineToEndAction lineToEnd = new LineToEndAction(line, this.text);

            this.actionManager.Do(lineToEnd, "Add");
            this.method = "Add";
            showInformation();
        }
        private void btnRemoveLastLine_Click(object sender, EventArgs e)
        {
            string line  = this.txLine.Text;
            int    index = Convert.ToInt32(domainRemove.Text);

            LineToEndAction lineToEndAction = new LineToEndAction(line, this.text);

            this.actionManager.Do(lineToEndAction, "Remove");
            this.method = "Remove";
            showInformation();
        }