private void btnPreferences_OnClick(object sender, EventArgs e)
        {
            Form fcbp = new frmClipBoardPref();

            fcbp.Show();
            LoadPrefs();
        }
        // preferences

        private void button1_Click(object sender, EventArgs e)
        {
            if (cbp == null)
            {
                cbp = new frmClipBoardPref();
            }
            cbp.MyParentForm = this;
            cbp.Show();
        }
        // called from preferences diag form
        public void ChangeFont(Font tf, float tfs, Font ef, float efs)
        {
            Font tfont = new Font(tf.FontFamily, tfs,
                                  txtTibetan.Font.Style, GraphicsUnit.Point,
                                  txtTibetan.Font.GdiCharSet, txtTibetan.Font.GdiVerticalFont);

            txtTibetan.Font = tfont;
            Font efont = new Font(ef.FontFamily, efs,
                                  txtTrans.Font.Style, GraphicsUnit.Point,
                                  txtTrans.Font.GdiCharSet, txtTrans.Font.GdiVerticalFont);

            txtTrans.Font = efont;
            cbp           = null;
            SavePrefs();
        }