It is not clear whether this is intended or is a bug.
If you forgot the title you might not be able to find it again!
More on this: a more advanced search is now available where you can search by author (now you can find your own documents). And Notifications are now enabled for those documents in your workspace. So you should be able to remove your own documents from your workspace in case you no longer wish to receive notifications on them.
Clearer icons have been introduced for the action 'delete variant' and the action 'remove document from workspace'
This is intentional. A more advanced search facility is required, e.g. to be able to search according to document owner/author. This would allow you to recover your own documents.
You won't be notified about changes to this idea.