       private void CopyToolStripMenuItem_Click(object sender, EventArgs e)
        {
            cutText = RichTextBox1.SelectedText;
            RichTextBox1.Focus();
            RichTextBox1.Copy();
            PasteToolStripMenuItem.Enabled = true;
            CopyToolStripMenuItem.Enabled = false;
            CutToolStripMenuItem.Enabled = false;
            ClearToolStripMenuItem.Enabled = false;
        }
