Totally agree, but you lose the DSP engine don't you? I always do?! I wish you could just use Connected Media in standard view as it is so much easier to use and doesn't require a separate device either (which I don't have right now anyway^^). I'd also like to use my mouse and right click in Theater View like in version 16 ) But hey, progress is in the works I think
I don't ever lose the DSP engine (my speakers don't work at all without the DSP engine), and web popup windows work just fine for me (including NPR). Even other music players/apps work just fine (I can loopback Amazon's cloud player for instance if I want to).
I'm not sure why your setup works so differently from mine, but it might be that you're trying to use it with only one device (are you using your MoBo sound right now?). I'm guessing that's why you're having trouble. If you have a second device, you just set that device as your system default and all system sound (from whatever source, even web popup players) can be looped back and fed through JRiver DSP.
Also, I'm not sure I follow why it matters what the URL of the service is if you're opening it outside of JRiver? Loopback is opened the same way no matter what, right? You can just start loopback in JRiver, and then navigate to whatever you want to listen to in the external browser/program and it will play, or does that not work in your setup?