Rated 4 out of 5 stars

Error: An exception occurred.
Traceback (most recent call last):
File "resource://jid1-xeaurv8gzibudw-at-jetpack-peek-lib/main.js", line 147, in
var container = window.gBrowser.tabContainer;
TypeError: window.gBrowser is undefined

This review is for a previous version of the add-on (1.0.1-signed).