I think you have to create a non modal Mainwindow like this:
[...]
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDR_ICO_MAIN));
wc.lpszClassName = L"vinfo_w3Class";
if (!RegisterClass(&wc))
return 0;
hwnd = CreateDialog(hInstance, MAKEINTRESOURCE(DLG_MAIN), NULL, (DLGPROC)MainDlgProc);
if (hwnd == NULL)
return 1;
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
and the following window you can create non modal or modal with the
DialogBox-Function.
I never tried it, but I think it should work