[chaley]

Originally Posted by userbooknerd

In the "Category Editor" https://share.getcloudapp.com/o0uEz1vA, there are great options for delete, rename, and under... but I don't see a way to add to this list.

Although this isn't what you want, you can sort-of add items in "Manage X" if X is a tags-like column. For example, with tags you can edit a value and add more tags to that line, as in "123" -> "123, newTag, blah". The new tags will be added to all the books that already have 123.

The same thing works with the "Rename" context menu command in the tag browser.