+1 I have a contact that won't let me do this either. I can do it for other contacts, but for some reason I too have no contact list appear. Maybe it's a bug.
I have the same problem. I have a Facebook contact, and a personal contact. They're the same person, but they used their middle name for Facebook. Whenever I want to join them, they won't show the list.
I've had to go into my google contacts and change a number of people to get the suggestions to work better.
Seems like an app to unify it all (gmail, phone specific, facebook contacts) would be really nice here. Maybe its time to put on my Android development hat =)
Go to contacts -> Menu Key-> click 'Edit' -> Menu Key-> click 'Join'
Mine works fine... I would just copy what ever # or info and paste it into one ID tag.. then delete the old one... Mine works fine though.. FYI the names have to be spelled exactly the same to get facebook to work.
I've also noticed that the linking with Facebook usernames doesn't happen immediately. If you change their name to mimmick their Facebook name, it took my Droid a couple minutes before they were linked up.
I do wish there was an option in the contacts app to manually link them up with a Facebook contact.
I had the same problem and tried everything. I then noticed that under display options I had checked "only contacts with phones" I unchecked it and the contact that I needed was there.
Some just wont merge for me either. Some suggest stupid contacts but at least it has the option to view all contacts. I don't know why some don't have anything listed at all.