The following program displays a window with a status bar.  Both the
window and the status bar display size grips (the /// in the lower
right corners), but I think it is incorrect for the status bar to
display one since I did not specify SBARS_SIZEGRIP in the status bar's
CreateWindow.

I am looking for an answer that does either of the following:

1) Uses official Microsoft documentation or publications to explain
why the observed behavior is correct & how to get the desired behavior
without resorting to a workaround (I already know that clearing
WS_THICKFRAME when creating the main window & setting it later is a
workaround), or
2) Uses official Microsoft documentation or publications to show that
this is a known bug.

#include <windows.h>
#include <tchar.h>
#include <commctrl.h>

int APIENTRY _tWinMain(HINSTANCE hInstance,
                       HINSTANCE hPrevInstance,
                       LPTSTR    lpCmdLine,
                       int       nCmdShow)
{
        InitCommonControls();
        WNDCLASSEX wcex;
        wcex.cbSize = sizeof(WNDCLASSEX);
        wcex.style                      = 0;
        wcex.lpfnWndProc        = DefWindowProc;
        wcex.cbClsExtra         = 0;
        wcex.cbWndExtra         = 0;
        wcex.hInstance          = hInstance;
        wcex.hIcon                      = LoadIcon(hInstance,
(LPCTSTR)IDI_APPLICATION);
        wcex.hCursor            = LoadCursor(NULL, IDC_ARROW);
        wcex.hbrBackground      = (HBRUSH)
GetStockObject(WHITE_BRUSH);
        wcex.lpszMenuName       = 0;
        wcex.lpszClassName      = "MyWindowClass";
        wcex.hIconSm            = LoadIcon(wcex.hInstance,
(LPCTSTR)IDI_APPLICATION);
        RegisterClassEx(&wcex);
        HWND hWnd = CreateWindow("MyWindowClass","MyWindow",
                WS_VISIBLE | WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN |
WS_HSCROLL | WS_VSCROLL,
                0, 0, 300, 300, NULL, NULL, hInstance, NULL);
        HWND hStatusBar = CreateWindow(STATUSCLASSNAME, "StatusBar",
                WS_VISIBLE | WS_CHILD, 0, 0, 0, 0, hWnd, NULL,
hInstance, NULL);
        MSG msg;
        while(GetMessage(&msg, NULL, 0, 0)) {
                TranslateMessage(&msg);
                DispatchMessage(&msg);
        }
        return (int) msg.wParam;
}