I can't remove empty bookmark tags

[KamiOh]

Hello, sorry my english.
I have this annoying problem,
try looking for any addons to edit the marker tags.
Without any success.

winbugs 10 ltsc x64 & Firefox 74 x64
https://i.postimg.cc/yxyFvfGk/7777d.jpg

[therube]

What is a "tag"?
How do you create a "tag"?

OK, found it, Bookmarks Manager (Ctrl+Shift+B).
(What an absolutely horrid interface, UI/UX!)

Looks to work for me (FF 77). [There is an update to your FF 74.]
I create a bookmark, assign it to a tag.
If I delete the tag, the bookmark remains.
If I delete the bookmark, the tag remains. If I then delete the tag, then it too is gone.