- changed status to closed
- When you clicked the first time "remove", what kind of 404 page did appear? One in the BibSonomy layout or one in another layout?
- How did you go "back"? Using the browser's "back" button or reloading the original page?
- Real duplicates should not happen, only when something really goes wrong.
- The duplicate was correctly removed in BibSonomy. However, your homepage is not updated in real-time. Hence, it still showed the duplicate. I re-initialized the corresponding Zope object and now everything is fine.