Tag suggestion only works for the first tag
- add a tag to a question. I chose bug for this question.
- add another tag. I chose tags for this question.
- Select with mouse (or enter) the second tag from the autocomplete list.
I would have 2 tags. In this case, bug tags.
The new tag replaces the original one. In this case I have: tags tags.
I have seen this behavior on all three sites.
This is with IE8 on Win7 if that happens to be relevant.