/// <summary>
        /// Open a Wintab context to the specified hwnd.
        /// </summary>
        /// <param name="hwnd_I">parent window for the context</param>
        /// <param name="enable_I">true to enable, false to disable</param>
        /// <returns>Returns non-zero context handle if successful.</returns>
        public HCTX Open(HWND hwnd_I, bool enable_I)
        {
            try
            {
                m_hCTX = CWintabFuncs.WTOpenA(hwnd_I, ref m_logContext, enable_I);
            }
            catch (Exception ex)
            {
                MessageBox.Show("FAILED OpenContext: " + ex.ToString());
            }

            return m_hCTX;
        }