I click on the Facebook tab, and nothing is visible, i only can see the profile submit buttons (Save and Delete).

After some debug i found out a couple of things and, like the other issue i opened today, i cant figure out how could this work to other guys. Here is what i found.

1. I saw the handler for user/*/edit/fbconnect in the hook_menu: fbconnect_user_identities, in fbconnect.pages.inc. I added a brutal debug breakpoint (die() on the very first line of the .inc file) and nothing happened, the tab still was there...empty. So the file have never been included.

2. I gave a look to the hook_user, and i saw the $op:'categories' return this category. Seems like that's overriding the hook_menu handler

3. So i went back to hook_menu, and changed
$items['user/%user_category/edit/fbconnect'] = array(
to
$items['user/%user/edit/fbconnect'] = array(

4. Removed the 'categories' handling in hook_user

Things began to work as expected now.

It's the first time i see this tabs management mode. I have 2 questions, to try understand what's the goal the develop team is willing to achieve.
Why use the hook_user to return information already specified in the hook_menu?
What's the point of that strange %user_category in the menu path?

Thank you, i think this module is good stuff but makes me confused about, and i cant get it work fine without debugging.