The developer is still transitioning Adblock Plus to Firefox 57, so much of the functionality has been temporarily compromised. In the meantime, I recommend not upgrading to Firefox 57 or reverting to Firefox 56 and using Adblock Plus version 2.7.1 to restore full workability. Addon rollback works for other addons annihilated by WebExtensions as well. Just make sure to disable Firefox automatic updates and set any Firefox-57-incompatible addons to update manually. Disabling addon compatibility checking and/or addon signature checking through about:config may be required, but I don't believe so.