Normally I would do Application.Run(myMainForm).
But I want to do something like this:
MyForm1 f = new MyForm1();
f.Close+=OnOpenOverviewWin();
Application.Run(f);
void OnOpenOverviewWin()
{
MyOverViewForm f = new MyOverViewForm ();
Application.Run(f); // i want to do this
Application.NewMainWindow = f; // or something like that
}