5 stars for the toolbar Version 1.2.13
The current version ( 2+ ) is useless.
New firefox does not support alot of stuff. That is why most of the developers I know keep an older version running and turn off the upgrades. Why don't you post a link to the older version of the extention in your blog?

UPD: https://04.yfhome.xyz/en-US/firefox/addon/web-developer/versions/ here is the link. Took me some effort to find it. Please post it somewhere on your website for everyone to see.