I had to decrease the font size (slider under hamburger icon) in order to get the tag feature (of an individual book) to work
Could you post an screenshot of the problem?
The following is assuming you are talking about the Information page of a resource?
You could try Ctrl-F11 to float the book full screen, that should allow you to see the tag bar, and then Ctrl-Shift-F11 to redock the tab.
Your thread title typo made me spit my coffee on my screen. [:D]
