Comment 1 for bug 1167538

This is nothing to do with either of the Ubuntu addons. It's actually an issue with older versions of Firebug. I suspect all that happened when you disabled our addon is that Firebug updated to the latest version when you restarted Firefox.

The issue affects Firefox users on all platforms, including Windows and non-Ubuntu Linux distributions

https://bugzilla.mozilla.org/show_bug.cgi?id=823072
https://bugzilla.mozilla.org/show_bug.cgi?id=832022
http://code.google.com/p/fbug/issues/detail?id=6346
https://bugzilla.redhat.com/show_bug.cgi?id=948688