I'm having difficulty with event stream connectors

I have created an event feed, which is just filtering on my user id.  

I can see events are coming through this feed:

However when I try to add that feed as a source for a Connector, the "sources" drop down is empty.

How do I get the event feed I have created to appear in the sources drop down? 

Additionally, the connectors seem to all have the WHEN Joined Audience bit at the end.  If I'm adding this as an event connector, do I still need to have this as a condition? Surely the point of a connector linked to an event feed is to fire it on every event (filtered by the feed) and not be limited by joining/leaving audiences?

Or is my understanding on this totally wrong?