Duh, shortly after posting I figured out that one has to click the little arrow to the right of the Device: line to switch from en0 ethernet to en1 wifi. Just goes to show that for some of us, this is not as intuitive as you think it is. Sure would be “sweet” if you had a short "How To Use" document posted somewhere that explains how to use the app.
For another example, what is the function of the “Update Address” button? I haven’t been able to figure out how/when to use that. Sometimes it is grayed out, sometimes highlighted in blue. Can't figure out what it is supposed to do, as compared with changing the spoofed address by clicking Randomize. I appreciate your hard work and have been a long time Cookie user. But we're not all developers out here with an intuitive grasp of a bare bones user interface. Thanks for your products.