With our borderless design, people can have conversations with your team on your website and web apps without needing to open the full Messenger:
Borderless conversations appear on the desktop web Messenger when you send chat full messages, and for all the conversation replies your teammates send.
Note:
When a user closes a borderless conversation, it returns to borderless again only when a teammate replies.
If a user has multiple unread conversations, they'll see a preview of all of them, and only upon opening one will it expand into borderless mode.
Can an end user trigger it?
No, borderless conversations only trigger from teammate messages.