TimerApp/Program.cs

namespace TimerApp;

static class Program
{
    /// <summary>
    ///  The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        if (!SingleInstanceManager.TryAcquire(out var instance) || instance is null)
        {
            SingleInstanceManager.SignalExistingInstance();
            return;
        }

        using (instance)
        {
            TaskbarIntegration.InitializeProcess();
            ApplicationConfiguration.Initialize();
            TaskbarIntegration.InitializeShortcuts();

            var mainForm = new MainForm();
            instance.StartServer(mainForm.ActivateFromExternal);
            Application.Run(mainForm);
        }
    }
}