# Hyphenated tags not working?

While trying to re-tag this question I've been unable to remove the tag kalman and replace it with kalman-filters. Whenever I try that, I just get left with the tag kalman.

The tag kalman was merged with the tag kalman-filters some time ago... and now it's back for some reason.

Other non-moderator users have edited that question and added a new tag... which is not what is required. We just want to use the hyphenated tag.