/*
 * The handler set the actual size of the window always
 * to be _WIDTH wide and _HEIGHT high.
 */
        case MSG_SIZECHANGING:
        {
            const RECT* rcExpect = (const RECT*)wParam;
            RECT* rcResult = (RECT*)lParam;

            rcResult->left = rcExpect->left;
            rcResult->top = rcExpect->top;
            rcResult->right = rcExpect->left + _WIDTH;
            rcResult->bottom = rcExpect->top + _HEIGHT;
            return 0;
        }