private void txtAction_TextChanged(object sender, System.EventArgs e)
    {
        bool bRet = oCLI.IsExecutable(txtAction.Text);

        if (bRet)
        {
            txtAction.BackColor = Color.LightGreen;
            btnOk.Enabled       = true;
        }
        else
        {
            txtAction.BackColor = Color.LightSalmon;
            btnOk.Enabled       = false;
        }

        return;
    }