delphi中登录界面关闭直接现实主界面是怎么回事？

修改工程文件：
Application.Initialize;
Application.CreateForm(TmainForm, mainForm);
 Application.ShowMainForm:= False;
if LoginForm.ShowModal then
    begin
     Application.ShowMainForm := True;
     Application.Run;
    end
else
begin
 Application.Terminate;
end;