The page comment locking functionality in bubbles allows an admin user to prevent any new comments or updates appearing on a forum topic page or blog post page.
This functionality is available in Bubbles 1.4 and later. It works using the servlet filter plugin type to prevent access to the comment actions when a page is locked. For more information on setting up page locking and the theme customisations required refer to Page Comment Locking Administration
If you have permission to lock page comments, you will see an option in the tools menu for the default theme. Once the page is locked no comments can be added, edited or removed.
(Depending on how the Confluence administrator has setup the theme, the links to add, edit and remove comments may still appear when a page is locked.)
If a page is locked (and you have permission to unlock it) there will be an option in the tools menu for the default theme.
(If a forum topic page is moved outside of a forum, thus no longer making it a topic, you will still have the menu option to remove the comment locking, but will no longer be able to lock the page again once unlocked.)