I'm building a tag generator. I think users should not enter/select a tag that has already been selected and users should be able to create new tags by pressing enter.
Here: https://harvesthq.github.io/chosen/ is always only a selection from a list of available. Once a value is selected it becomes disabled in the suggestion list - which for me seems great.
On the other way, I was thinking that users could just type and click enter to create tags. But if they have a typo or misspelling then that tag lives on forever? Jira has a control with a check and an X
What is the best way (or less annoying)? It wouldn't be frustrating if you had to click on the check every time you wanted to had a new tag (or a group of them), for instance... but It would be problematic if you had a massive amount of non-usable tags also...