I got something to report:

I installed the theme, applied, restarted, and then the application button wasn't available anymore. I had to launch the browser from a shortcut and navigate to install a random app, which invoked the app manager, which I used to un-install the theme, then rebooted and everything was fixed.

I disabled Advanced Backlight Control, installed, etc and it all went fine this time. Enabled ABC again and still fine.