Thread: flat menu problem

I'm trying to remove the 3d border from a windows popup menu and replace it with a simple 'flat' border (like ws_border). Whenever I try to set WS_BORDER and remove all styles and ex styles that would create a 3d border it doesn't work.
I have now subclassed the window so I can paint it myself, but when I call the old window proc I get a stack overflow.

Code:

...
lpfnMainMenuWndProc = (WNDPROC) SetWindowLong ( hMenuWnd, GWL_WNDPROC, (DWORD) MainMenuWndProc ) ;
...
LRESULT CALLBACK MainMenuWndProc ( ... )
{
...
    return ( CallWindowProc ( lpfnMainMenuWndProc, hWnd, uMsg, wParam, lParam ) ) ;
}

Am I trying to make a flat border the wrong way?

Thanks