I honestly don't know if this was part of the many existing bug reports on the library's behavior regarding the new tagging feature. So I report it.
The library is floated, filtered and grouped per edition, one group expanded: when I add a tag to a resource, the group immediately collapses.
Before adding a tag to the resource:
immediately after (I wish Logos was always that fast with sensible or user-invoked screen changes!):

The bug is repeatable even on the unfiltered library, positioning the library in an empty space with no vertical scroll bar. Before (editions Logos and ebook are collapsed, user is expanded) :

after adding a third tag to the resource:
Note there's no vertical scroll bar anymore. In this case it came back after I filtered for something and removed the filter to show all resources - in my prior attempt this wasn't the case and I had to close the library.
(in case you need it, I have saved the Logos.log, but I hope the reproduction steps are clear)
This bug makes tagging a less than pleasant experience...