I do not manage to get the 2nd tier “Main navigation” menu items to show in the main header menu.
Hello @onordahl,
You can have a look on my answer in Dropdown Horizontal Menu but instead of a sidebar menu block, edit the Main Navigation menu block placed in the header region. Let me know if it solves the issue.
Konstantinos
Yes, that solved the issue. I found the setting under /admin/stucture/block then “Main navigation”