How to delete a drive tag?

I appreciate that this is a very old topic - but it's the only one that came up on a 'Delete Tag' search. 
It appears that a tag will disappear if there are no more drives assigned to that tag.
For instance, I wanted to change to 'Work mileage' instead of 'Toil'.

I manually tagged one drive with 'Work mileage' to create the tag.

Then did a search in 'Drive Search & Download' for all drives tagged as 'Toil'.

Then over on the right did 'Tag all drives as' and selected 'Work Mileage'.

There was then nothing left assigned to 'Toil' and it seems to have vanished (which is what I wanted). Excellent...

Don't forget to change any auto-tag rules to the new information.

I did aswell, would be nice to be able to delete unwanted tags.