Re: Navigation collapsed - how to get the full menu visible again?
Could you post a screenshot? Are you using the default menu that comes with Tiki or did you create your own?
If menu items disappear it's either because the feature is disabled or the current user does not have permission to see those items, as determined by his/her user group.
You could try going to the tiki-admin_system.php (System Admin) page and clear all the caches.