/// <summary>
        /// Shows the form.
        /// </summary>
        private void ShowForm()
        {
            logger.LogInformation("+ ShowForm()");

            if (mainForm == null)
            {
                mainForm = new MainForm();
                mainForm.Text = "Window Manager";
                mainForm.FormClosed += MainForm_FormClosed;
                mainForm.Show();
            }
            else
            {
                mainForm.Activate();
                mainForm.Show();
            }

            logger.LogInformation("- ShowForm()");
        }
        /// <summary>
        /// Handles the FormClosed event of the MainForm control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="FormClosedEventArgs"/> instance containing the event data.</param>
        private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            logger.LogInformation("+ MainForm_FormClosed()");

            mainForm = null;

            logger.LogInformation("- MainForm_FormClosed()");
        }