Extraction Preview Won't Display Text When Appropriate Window is Open

I am debugging a program with a valid, working selector that points to text on this page, yet fails to extract it with the Get Text activity somehow. I am trying to use the Extraction Preview wizard to get to the bottom of this, but as can be seen in the screenshot, it won’t display text even when the appropriate website is open. If the selector is properly locating the text, then what else do I need to do to get the Extraction Preview working?

Have you verified the selector using UiExplorer instead of going with Extraction Preview?