Missing resource attributes in tempo labels (and values)

I want to set up dashboard variables using attributes from my Tempo data. My tempo data has several resource-scoped attributes, and no span-scoped attributes (yet). I’m following the post here: Querying a distinct set of values of an attribute for dashboard variables · Issue #3588 · grafana/tempo · GitHub

In that UI, and in the “search” ui that presumably uses the same API, I see label names come up, but my resource attributes are missing.

Do I need to have these attributes as span attributes (as opposed to resource attributes) in order for them to show up in this API/UI?

I found the issue. My traces are too old and are not being considered in the tag search. It seems like this search might need to consider a longer time, or perhaps add a UI for the user to specify the time window from which tag values should be considered?