One more glitch, though this has a simple workaround. Trainnews now apparently opens the target window within the Trainnews window (based on what I see in the title bar and the tab title. Some sites don't like that (such as Popular Mechanics for the hydrogen article) and reject the link due to a "content security policy" in Firefox. Workaround: I open the target site in a new tab under its own name. Not sure what's going on there, or whether it's just something Firefox is doing. Again, workaround is solid. Thanks for the service!