Except now the extension doesn't exist any more. Real dumb, as chrome STILL doesn't see the chromecast when it joins and now there's no way to force a refresh. So what else works? Disconnect from Wifi. Reconnect to Wifi. That's what works.
Like I said, sounds good on paper, fails in reality. For a company that claims to have a lot of PhDs in computer science, the number of buggy to unusable products they bring out is mindboggling. "Engineers" indeed. Mmmmm, mmmm!