I've been running Linux Mint Julia for a quite a long time now. Only yesterday I updated the entire system (including kernel, firefox, chromium, openoffice, pidgin and all that). Also changed my Login password due to some security reasons. No ugly surprises. No lag in performance. But everytime I started chromium browser it popped up a "Login keyring" message that read "Enter password to unlock your login keyring".
It seems Seahorse uses the login password as master password to unlock its passphrases. Sadly, when the user changes the password, it is not updated to Seahorse and that "Login keyring" popup comes up.
Visited both Mint and Ubuntu fora for a fix. All the solutions there from were pointing to Seahorse (two items in System >> Preferences: Passwords and Encryption Keys, and Encryption and Keyrings).
However, the easiest and unfailing fix to avoid this message it is to remove the ~/.gnome2/keyrings/login.keyring.