DO NOT INSTALL: writes instructions to userChrome.css Rated 1 out of 5 stars

WARNING: This extension writes a whole section of instructions to the userChrome.css file. As a result, when it is uninstalled its detritus is left behind, which causes a whole mess of error messages to be written to the error log every time Firefox is restarted. This means this add-on could be causing you problems long after you think you have uninstalled it.

I would advise against installing this add-on until the author rewrites it such that it doesn't write instructions to the userChrome.css file.