I am using 1.0-rc19 version. I made a global ACL file in /etc/dovecot-acls/Public as: owner lrsi user=manager rl

The owner cannot delete/move mail inside his Public folder as I want. But the user "manager" cannot subscribe/view to other's Public folder. What I have missed?

Make sure your acl file ends with LF (there is an empty line at the end) otherwise dovecot doesn't read the last line.