Rated 4 out of 5 stars

I love this extension. All bugs fixed on github https://github.com/janodvarko/PixelPerfect/commit/0f57f6355f68280c37da6b6f6a8331a40d4e4060
Works with latest version of Firefox and Firebug

This review is for a previous version of the add-on (1.8.0.1-signed).