Why is destructor for a form called twice?

This code with entry point calls form's destructor twice.

void Main(array<String^>^ args)
{
    Application::EnableVisualStyles();
    Application::SetCompatibleTextRenderingDefault(false);
    MyApp::MyForm form;
    Application::Run(%form);
}

I have changed it to

void Main(array<String^>^ args)
{
    Application::EnableVisualStyles();
    Application::SetCompatibleTextRenderingDefault(false);
    Application::Run(gcnew MyApp::MyForm);
}

The second version calls destructor one time only.

Why initially was it called twice?