Can't create new tag and change category at the same time

[nathank (Nathan Kershaw)]

Worked it out:

It only happens when the tag doesn’t yet exist. I can change categories and tag with an existing tag, but not with a new tag.

A bit similar to this, eh?

Adding a new tag in the default tags fields

Yes we should certainly fix this. @vinothkannans can you add a validation on those tag settings?