Can't get tag to work

I have a dashboard with several prebuilt panels and several non-prebuilt panels. At the top of the form I have: Refresh1 minute5 minutes10 minutes15 minutesNeverNever For the value attribute I have tried integers (as above) and SPL time formats (e.g. 5m). Within various searches in both prebuilt and non-prebuilt panels I have added: $refresh$ shown in several online postings as well as the documentation for our version of Splunk: 6.6.2, build 4b804538c686. Nothing I have tried seems to work as I expect. The prebuilt panels run once and stop. The non-prebuilt panels refresh every minute. I think (it's a little hard to tell by hovering over the little controls). Am I doing something wrong here? I have other dropdowns on the page that work, and the variables defined by those dropdowns interpolate in the prebuilt panels. If I add $refresh$ to a panel title it shows up just as I expect. As far as I can tell the tag does not work, or at least it does not work as I expect. I have tried constants in it and they don't seem to change anything. Then once in a while it surprises me in some non-reproducible way. Can someone tell me what I'm doing wrong?