When I go to a red-marked-dead site and try “Retry fetching and parsing”, it stays a while and then the dialog closes, the site remaining red-marked-dead. Instead of this I would expect a message to be displayed in the dialog saying that the feed’s URL is finished and I should try something else (maybe the site’s changed the feed’s URL and I should go find it, etc.).
Yeah, this whole dialog has gone through multiple revisions and could use another one. Unfortunately, it’s extremely difficult to get this right, because when I’m trying to fix a broken site, it sometimes has the habit of getting fixed and then I no longer can test it. And building test cases for complicated setups like this is near impossible. This will have to wait, unfortunately.