Thanks all. Right you are. Turns out I had some other kind of problem going on.
None of the xml changes i made were actually having effect. I played with the backdrop code for a while, and then finally gave up and tried something simple like just changing the color of some text. That didn't work either.
I finally had to make a new theme folder and copy the files over. Then after enabling the "new" theme, the changes worked.
Very odd . . . then a short while after this, I noticed some other strange problems. Backgrounds on EVERY view were missing, and then the whole hub crashed, and would not restart until I pulled the power to reset. I hope this isn't a sign of my hub dieing