I think I found a filtering bug in JIRA but I apparently don't have an account on your server to report it. We have version 1.4.2-#22 but I also found it on your site (jira.atlassian.com). If I filter with an incorrect user login, all the rest of the filter settings are lost because they revert to those of the previous search. If I choose to "View and Hide," I will not even see the error message at all, but I will see the results of the previous search, which therefore could be mistaken for the results of the current filter.