BTW one possible behavior is to move the old tag to the end, providing both
feedback and function

вт, 3 сент. 2019 г. в 16:29, Dmitrii Korobeinikov <dim1212k@gmail.com>:

>    org-set-tags-command allows duplicates. Example:
>    - M-x org-set-tags-command -> "tag"
>    - M-x org-set-tags-command -> "tag"
>    Result:
>    * Title    :tag:tag:
>
>    I think it would be handy to prevent this.
>    Not unimaginable that someone could use this as a feature, though, in
> which case, a flag would be nice.
>
>    Regards,
>    Dmitrii.
>