try this:
Local combohwnd=SendMessageA(QueryGadget(combobox,QUERY_HWND),CBEM_GETCOMBOCONTROL,0,0 ); SetWindowPos combohwnd,0,0,0,120,400,SWP_NOMOVE|SWP_NOZORDER|SWP_NOREDRAW|SWP_NOACTIVATE