I've read a lot of post and answers on this, but....  For most contacts that I want to delete, if I "right-click to interact", as the program tells me, the Delete option is pale, and does not respond to any click.  In most attempts, the "RED" cross in the ribbon remains blue!  Only if the label: "Address Book" appears under the Contact name will the "Red" cross be red, and clicking the Delete is then successful.

   Some Contacts are labelled: "Facebook" (and I have gathered that they can be deleted "from a Facebook" account); but what about those Contacts which have no label?  How can they be deleted?