Its extremely simple: to tag a new reference with e.g. three different tags one needs to write out all 3 tags with line breaks. it would be tremendously easier to have a pick list of all existing tags and click on multiple. would be a dream come true and finally I would tag all refs accordingly and get to organize my 1000+ refs
used to be able to see a list of existing tags when adding tags to a paper (Papers 3). Now that has gone, one has to remember what tags might there be (I have >50) so this is almost useless. Tagging was the main way I used to organise my library. Also bring back ability to tag multiple articles at once
Dragging and dropping references on a tag should tag those items.
It would be nice if you could also drag/drop an article onto the tag in the smart tag list to add it as a tag to the article.