I can not call the forms declared in Form1.h

[Noreturn]

In the MSND library, i saw such an example to display user defined dialogs;

{

Form ^ f = gcnew Form();
f->ShowDialog();
}

And i changed this code to display my About.h form dialog such as;

{

Form ^ About = gcnew Form();
About->ShowDialog();
}

But, i still see the same empty dialog instead of my About.h form. So how can i display this dialog when i click About menu ?