Thanks. I tried that, but it made no difference. However, doing this made me notice a few things. I have three Smartthings plugs. Two are round and say “Smartthings Outlet” and one says “Samsung Smartthings” and it is shaped differently. The one marked Samsung works as expected in the dashboard, but the other two do not. Also, the two that don’t work in dashboards don’t report Last Activiy in the device list. Curious.
Yay!!! Configure did the trick! I had pressed that before (on other devices, I suppose) and couldn’t notice a difference in the page. This time I saw that it added Current State to the Device page and Last Activity to the Device List. Both are now working in Dashboard. I have learned a lot. Thank you all very much.