PROBLEM
The inline footer to directly blacklist senders doesn’t work as expected and adds an empty sender line to blacklist.
SOLUTION
This is a small bug in version 3 upgrade. To fix go to menù System->Logo and Message Customization. Edit inline html signature and correct blacklist hyperlink by adding at the end of the link $id.
The correct url should look like:
http://address/cgi-bin/learn-msg.cgi?blacklist=1&id=$id