I created a Views page and wanted to place it as a secondary task (tab) under admin/content.
I added an entry to my custom module's links.task like this:
mycustom.admin_orphaned_pages: title: Orphaned pages route_name: view.orphaned_pages.page_1 parent_id: system.admin_content
and this works to now add a secondary task under the Admin Content page.
The issue is, when I go to this page, it loses the primary (and therefore other secondary) tabs. Is there something missing here?