I am using 2.2 - and here's what I found:
the category had NOT saved the extra field group selection - BUG I guess?
Once you fix that, you go to create an item, and you select a category that has extra fields and it won't let you use them UNTIL you click apply, then they show up - sounds like another BUG?
Still can't apply tags, which was the whole reason I even installed this thing - any idea what's up with that? They're in the list, but I select one and click add and nothing happens...