I realized that choosing Custom Menu, to show just the pages on there I want, in the order I want, breaks the ability of the menu to display a drop-down showing the child and grandchild levels of pages that have them.
The various code examples I see in old, closed WP forum answers to this issue does not appear in this or any theme's php or css, that I can find. They typically say something like:
<?php wp_list_pages('title_li=&depth=1'); ?>
but "depth" can not be found in any code i can find.
I assume this would be in the functions.php but I have looked in all of them.
The moment I delete custom menus and go back to the default the drop downs appear.
But I do not know code at all, so I do not know a)where to find the menu code and b) what parts I should replicate in the custom menu and C) WHERE I would find the custom menu code to put the correct code for child drop downs.
Any suggestions would be most appreciated.