Problem:
1. In the tag input field, I can only enter text.
2. I have no idea, what separator to use to separate different tags (,?). At least, it is not intuitive and I'd have to look it up into the doc.
3. From the web, users expect a different UI for tags.
Solution:
IMHO the UI should be redesigned to match the common tag "UI" one knows from the web. See http://ui-patterns.com/patterns/Tag for how it looks. Basically it is just so that a box should be around each tag, and they are automatically added when I type the text in the input field. When I type "," (or maybe other separators too, so users can use what suits them) it should automatically convert the previous text into a text (i.e. display a box around it) and let me continue to type the next tag. Thus, it is clear to the user when a tag ends/what separator it uses, and they can intuitively add their tags.
Also it should suggest previous tags, so users don't accidentally add typos and their tags get different or so.
yes things to improve out there
2. read the doc: http://