Since today EHH does not function. It is enbled in the Add-on Manager but it does not show up in the ABP context menu and the shortcut key does not work either.
I have to disable and enable it immediately in the Add-on Manager to make it work again.
Adblock Plus 2.1.3a.3568 + EHH 1.2.4a.436 on Firefox 16.0.2. Reproducible on a fresh FF profile.