If in Labregister a Category is definitely no longer needed, if only because (e.g.) another Category was copied unnecessarily, then this can be done as described below.
- Click OPTIONS.
- Click Delete category.
- A pop-up will explain what is going to happen. Click DELETE to execute.
Tip: As you can see in the screenshot for point 5 of "How to unhide", it is also possible to delete a Category while hidden. It is therefore always advisable to hide a category prior to (possibly) deleting, to give users the opportunity to object.