I have the same issue but with mail-notification-applet, under Gentoo: mail-notification doesn't read (and write) passwords from gnome-keyring (Each 5 minutes mail-notifications asks for the password of my mailboxes). When I log out and log in again (without restarting), mail-notification works normally and can read and save passwords. It is a problem of gnome-keyring, not a problem of nm-applet.
I have the same issue but with mail-notificati on-applet, under Gentoo: mail-notification doesn't read (and write) passwords from gnome-keyring (Each 5 minutes mail-notifications asks for the password of my mailboxes). When I log out and log in again (without restarting), mail-notification works normally and can read and save passwords. It is a problem of gnome-keyring, not a problem of nm-applet.