I can tag issues in MantisBT and feel that there would be a lot of value to adding a filter for the extension to query based on a tag.
Topic on Extension talk:Mantis
Support for filtering by "Tags"
This sounds like an interesting idea, but that code change would be extensive. Also, how exactly would you handle a new parameter tag?
Let's say one enters 2 tags. Should only tickets be listed that include both tags or tickets that are tagged with either tag?
Pull requests are always welcome.