private void toolStripSplitButton1_ButtonClick(object sender, EventArgs e)
        {
            toolStripComboBox1.Items.Add(webBrowser1.Url.ToString());
            FileStream fs = new FileStream(@"C:\AvatalkBookamrks.txt", FileMode.Append);
            if(fs.CanWrite == true)
            {
                StreamWriter sw = new StreamWriter(fs);
                foreach (string Url in toolStripComboBox1.Items)
                {
                    sw.WriteLine(Url);
                }
                sw.Close();
            }
            fs.Close();
        }