Can't overwrite menu entries in _menu_append_contextual_items()

Hi,

in my module I want to overwrite some menu entries made by the user.module. So I have given it a weight of 5 in the system table. Thus my_module_menu() is called after user_menu() and my module overwrites the entries of the user.module in _menu_build(). That's fine. But some menu entries are dynamic and added in _menu_append_contextual_items(). However, in that function existing menu entries are only overwritten if their type contains MENU_CREATED_BY_ADMIN. This leads in most cases to the following behavior: If we have a module a with weigth of 1 and a module b with a weight of 2 and both modules implement menu_hook($may_cache). Then the menu entries from module b prevail for cached menu entries ($may_cache = TRUE) and the menu entries from module a prevail for uncached menu entries. So how can I achieve that my module can overwrite all menu entries made by user.module?

Regarding the callbacks there is something strange going on in there.

if (isset($item['callback'])) {
      $_menu['callbacks'][$item['path']] = array('callback' => $item['callback']);
      if (isset($item['callback arguments'])) {
        $_menu['callbacks'][$item['path']]['callback arguments'] = $item['callback arguments'];
        unset($item['callback arguments']);
      }
      unset($item['callback']);
    }

is executed in every case. So the $_menu['callbacks'] are updated even if the new entries are not set in $_menu['items'].

if ($_menu['items'][$mid]['type'] & MENU_CREATED_BY_ADMIN) {
        $_menu['items'][$mid]['access'] = $item['access'];
        if (isset($_menu['items'][$mid]['callback'])) {
          $_menu['items'][$mid]['callback'] = $item['callback'];
        }
        if (isset($_menu['items'][$mid]['callback arguments'])) {
          $_menu['items'][$mid]['callback arguments'] = $item['callback arguments'];
        }
      }

Why the $_menu['items'][$mid]['callback'] = $item['callback']; statement? $item['callback'] is always unset (see above).