Desktop.cpp中BOOL CDesktopWnd::Create()有如下语句:
SetRect(&rc, 0, 0, GetSystemMetrics(SM_CXVIRTUALSCREEN),
GetSystemMetrics(SM_CYVIRTUALSCREEN));
// create the desktop's view window (no need to AddRef since CreateViewWindow
// does it)
hr = _psv->CreateViewWindow(NULL, &fs, (IShellBrowser *)this, &rc, &_hWnd);