"Ulrich Czekalla" <ulrich.czekalla at utoronto.ca> wrote: > + if (control->hwnd) > + { > + WNDPROC oldproc = (WNDPROC) SetWindowLongW(control->hwnd, GWLP_WNDPROC, > + (LONG)MSIRadioGroup_WndProc); I'd suggest to use SetWindowLongPtrW even it's just a macro in Win32 we still need to write 64-bit clean code. -- Dmitry.