I added tags to files, but the tags do not show in the left pane to filter tags.
Maybe I missed the question?
Tag filter is a “type ahead” feature
Do your tags not show if you start typing?
When I first used this feature I also wondered about where the tags were gone. Usability wise the tagging feature is not implemented well enough. I think a tag cloud would be much more userfriendly
+1 Great idea.