What versions of node-red, dashboard and nodejs are you using. If you start node-red in a terminal and copy/paste the startup log you get there then that will tell us that and possibly other stuff that may be useful.
Can you post a screenshot showing the tabs and what you see in the dropdown list there? You can paste an image directly into here.
Node Red is v1.0.2
Node.js is v8.9.1
Dashboard is v2.6.2
This is an original install of Node Red from maybe a year ago, which I looked at then but have now just come back to. I have updated Node Red itself and imagined that the dashboard gets updated too. But maybe that's not correct?
Bad news: The updates seem to have broken the TTN node i was using for all the data input! There's now an error that TTN app is not registered. But there's no remove option on this node to try reinstallation, while attempted reinstallation anyway tells me the node is already installed.
What version of node.js did you upgrade to?
If you changed the major version, you'll need to run npm rebuild in your ~/.node-red directory to rebuild the binary components of any modules.