It is no more possible to filter the results in the FireLogger console by log level after a recent Firebug update.
Firefox v. 23.0.1
FireLogger v. 1.2
Firebug v. 1.12
O.S. Ubuntu v. 10.04
I just released the latest code from github as version 1.3. It is in AMO review process now.
You may try to install it from this URL:
https://addons.mozilla.org/en-US/firefox/addon/firelogger/versions
On my OS X 10.8.5 with Firefox Nightly 26.0a1 and Firebug 1.12.0b7 the test page seems to work fine.
Thanks a lot
Luca