I will often have passwords for cites the have "(no username)". Didn't really understand this til today. When I tried to add the username I used for a frequented cite to the newest existing password that had (no username) and Firefox told me that username was already in use. There seems to be a bug that when updating passwords Firefox will not understand the extended cite will be connected to the main, maybe because the link will have an extra few letters. When adding the password Firefox will add it under (no username) for the main cite. Having a merge of the latest password for major cite and the Username for that cite will help not going individually each cite updating the password of a username or deleting whole passwords to re-add them.