My Default_keyring is locked at boot, but will unlock without giving password

[Barry Fishman <barry ecubist org>]

When I login to Gnome3 (on NixOS):

1) If I use mailnag-1.3.0 with libgnome-keyring my passwords are found.

2) If I use mailnag-2.0.0 with libsecret I get an error that the
   passwords are blank.

3) When I run the seahorse application my Default_keyring is shown as
   locked, but my Login is shown as unlocked.   I can unlock it by
   clicking on the lock symbol, and it values are displayed.  I am
   not asked to give my password.

   If at this point I restart mailnag, it finds my passwords OK
   If I logout and log back in the Default keyring is locked and
   mailnag fails again.
   
Why is the Default keyring locked at boot?  It doesn't seem to be a
problem with the pam setup, since it seems to know what the password is,
and the libgnome-keyring interface works.

Is there some option that needs to be reset?  This problem exists with
both gnome-keyring-3.34.0 and gnome-keyring-3.36.0.

--
Barry Fishman