As of today, I am officially withdrawing my development support for the Googlebar Lite Firefox extension. I'm aware that the extension no longer works well in the latest builds of Firefox, and I have absolutely no desire to fix them. Mozilla's development environment has gotten pretty irritating as of late, and I just don't have the cycles (or the drive) to fix the issues that exist.
The future of Firefox add-ons lies in WebExtensions, and toolbar support in that arena is pretty bare-bones (last I looked). The default Firefox search box meets most needs, which has motivated me to drop this extension.
For those that are so-inclined, I will accept pull requests at the official googlebarlite repo. Or, you can fork the project and roll your own.