Does anyone know why this happens in Facebook ?

did you unfriend him?
did you block him?
are mutual friends liking his comments?

If you don't want him showing up you should block him.
If you don't want him showing up on chat you can also disable chat for specific users.

I'm not sure exactly why he is showing up exactly where but the bottom line is that FB generally uses algorithms to prioritize people to whom you are more closely connected, and being a former boyfriend it is natural that they would have signals that you and he are closely connected.

If you do not want them to show him to you you need to send them a strong signal (i.e. blocking him) and they will stop doing so.

Yeah I unfriened him weeks ago and deleted all the messages. And we don't have any mutual friends. So its just a but strange he appeared the last week or so.

If he's unfriended but not blocked, FB will continue to show you his activity/posts.

The only way to completely make him disappear is blocking.

But I'm not seeing his activity or posts. Like there's no trace of him on my Facebook . Its just on the sidechat bar. I don't really want to block him he never done anything wrong so I'll just deal with him there I suppose 😊

so it's just showing that he's logged in on the chat bar? have you checked to see if he's sent you a message request ?

We never had in a relationship or anything there's no photos of us tagged together so he was just like a normal friend on Facebook. I've deleted others and they never appeared. So I'll just leave him there and maybe it will dissaper, I don't want to block him it looks strange after a month of not speaking. I was just confused why he popped up. Thanks for your message anyway 😊

No it just shows him on my chat bar I can't see if his active or not. No there's no messages from him and the messages we did sent I deleted them a month ago. I was just curious to why he was there maybe its a fault.

Since you've unfriended him, a new message from him wouldn't appear in your regular message line. It would be in the new Message Request section FB added.

Then again, it could just be a system glitch.

Yeah I've checked all the other folders he never sent me a message its probably just a fault.

If anyone unfriend other user on Facebook as well as remove all messages then I don't think that person/user will appear in the chat bar.

if you want you can report that account. is he blocked from your account ? if no then first block him and then report about his account after that he will never appear in your chat window.

Yes, unfortunately blocking is the only option here, because FB already has a record that you were in contact with this user many times and for a long time, so even after you unfriend him FB has still this info somewhere in storage and shows it to you as a suggestion...

did you unfriend him or not???

It is showing up as it might be the most frequently contacted person. If you block him then it won't show up. Later on you can unblock him once it stops showing up.

Whoever you had a chat with a person friend or not they will show on your side chat bar. So just unfriend won't make him disappear.