You must click Publish or Save Draft on the page or post for any Multicollab activity to save on your website database. There is currently no autosave feature for Multicollab.
When a comment is opened, it means (authorized) users can view it, mark it as hidden, mark it visible/show, reply to it, mention people below it, and can delete it.
When a comment is deleted or resolved, it is removed from the editing screen but saved in the Activity Center. All contributions to the resolved comment (replies, mentions, attachments, etc.) are also saved, along with the name of the contributor and the timestamp of the action.
Keep in mind that no Multicollab action saves until the authorized user saves the page/post as a draft, publishes the page/post, or sends the content for review (Status – Pending).