When I try to use my categories, the name of the category appears in the To: line with a + in front of them. When I click on the +, to expand the category, the category disappears. If I add email addresses after the category name, the email goes only to the added addresses as if the category wasn't there.

I checked the "Sent mail" folder only to find that the email went to the added addresses only. What's happening and how do I correct the problem?

BTW I tried the same operation in my Office Outlook account and everything worked just fine. So the problem seems to be with the Live Mail Account only.