Rated 3 out of 5 stars

doesn't work with Fx 4.0b4pre.

Error: MSG_ALERT is not defined
Source file: chrome://venkman/content/venkman-utils.js
Line: 286
Error: console.commandManager is undefined
Source file: chrome://venkman/content/venkman-static.js
Line: 281

This review is for a previous version of the add-on (0.9.88). 

Oops! Yes, you're right. I've fixed the problem, the fix is in, which will hopefully be approved by AMO soon. Thanks for pointing this out!