I was trying to edit the post "Big Bang Anybody?" by adding a popular-science tag to it.. While until now, even if I didn't edit the body of the post, I could still edit the tags. However, it seems like from today onwards, to edit the tags, I also need to add 6 characters to the text! At first, I thought of simply adding the followsing text:
$$\mbox{ }$$
However, I realised that then the edit would be rejected (since it is too trivial) and so will the tag edits .
So, why do we need to modify the text body just to edit the tags?