On a fresh drupal:
1. install the module
2. you don't see the menu
3. go to Blocks page, and the menu appears immediately!
This seems to me like a defaults problem -- the wrong default value is being read somewhere, or none at all, and it's only visiting the blocks page that's loading it.
Comments
Comment #1
sunSorry, this is known bug and admin_menu is already doing a block_rehash() in admin_menu.install to try to circumvent this.
Marking as duplicate of http://drupal.org/node/179648