You appear to be reaching the field size limit for the additional operations section. The current setting is 100 characters for all fields. To increase this to 255 characters the following command would need to be run using a tool like PhpMyAdmin. Alternately you can browse to
http://example.com/mail/editconf.php?customcmd=1 replacing example.com/mail with your ListMail domain and folder.
ALTER TABLE lm_lists CHANGE addopts addopts TINYTEXT NOT NULL
I have added this change to the next ListMail update for all.
This would fall in line with Can Spam laws since when a user request to be unsubscribed we are supposed to by law take them from every list they are on in our company.
Do you know about the new Remove Link options? You can now set up remove links to remove users from all lists. Using this you might not need to use additional options at all. Click 'Edit' next to your Remove Link message code.
Regards