For some reason I am unable to use on Stack Overflow. Does anyone know why this happens, and how to fix/get round it? Is it a website error?

To clarify, it allows me to type it in on the tags, but as soon as I save edits or post the question the tag disappears?


1 Answer 1


is a synonym of .

Whenever you use , it will be replaced with - and if you already have , it will be removed (no duplicate tags).

  • They can't be used in-conjunction with eachother then? So how can Python and Python-2.7 or Python-3.x be used in-conjunction and be allowed?
    – Hyflex
    Commented Sep 30, 2013 at 13:38
  • 1
    @Hyflex - The python tags are not synonyms (or at least, no one has defined them as such).
    – Oded
    Commented Sep 30, 2013 at 13:38
  • 6
    @Hyflex: Because Python != Python 2.7 != Python 3.0. In contrast to Twitter, because if you have a question about Twitter it can only be about the API, everything else would be off-topic on SO. Commented Sep 30, 2013 at 13:40
  • 2
    It got me too in the past, I must admit it wasn't easy to understand even when I was familiar with the synonym mechanism in general. Can the UI be improved somehow to add message like "this is a synonym and can't be added directly"? Commented Sep 30, 2013 at 14:36
  • @ShaWizDowArd silent, seamless translation is the point, otherwise "synonyms" could be dropped in favour of simple tag ban. I would like to see a message after save, like " Tag X was synonym of Y, replaced for you", or "Tags X and Y are synonyms, Y removed".
    – Mołot
    Commented Sep 30, 2013 at 14:42

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