Update Gnome2 Key Storage password from antique harmonised login & LUKS one

Edited; hopefully to make more clear.

An old login password (twice since replaced) still seems to be the Gnome2 Key Storage password. Upon changing my (sole admin/user) login password (using System Settings GUI) I expected Ubuntu to update this password in the same way that it seems to try to change the LUKS password. Perhaps that expectation is an error.

As recent login password changes haven't been flawless (I posted a separate question about that here) I wonder:

• if these passwords should be harmonised by Ubuntu during login password change
• how I change the Gnome2 Key Storage password manually.

That is two questions, I know, but they're linked to resolving the same issue of harmonised passwords forking which is dangerous for less knowledgable users.