As an editor of a question that someone else posted, when I go to try to make the question better by editing the title, changing grammar, etc., I'm forced to also give the question a new tag. What is the intent?
To reproduce: go to facebook.stackoverflow.com. Find a question that has only Facebook related tags on it (because it was asked via stackoverflow.com). Edit the question.
Expected: any reasonable edit allowed.
Observed: You must add a non-Facebook tag.
Workaround: Changing URL to stackoverflow.com allows edit through.