The 'more' entry on that menu is to allow customizing that menu, not the larger one you showed screenshot of.

I do not understand your concern about addressbook

Have you tried it. When I click on a name in my address book it open up a pane at the bottom with the details on that entry. But then there is no way of recovering to a full pane with all the addresses.

The problem is that 'more' should show up on the right and it does not on my three computers upgraded to 102. So I have no way of customizing the message header.

Looking at the addressbook, there is a search box with an icon to the right. If you click that icon, you can switch from horizontal to vertical view. On your comment about 'more' not showing up, you posted a screenshot of it earlier showing up. I don't understand what you mean.

Thanks for your effort on this. Still no way of returning to full pane on the address book.

And what you are looking at is the example I copied from TB. The other larger one is my computer where 'more' does not show.