Per the documentation, once a space is archived, it "won't appear on any drop down menus".
After archiving a space I am still seeing the space in a dropdown menu.
(Verified it does behave appropriately (i.e. it doesn't appear) when I try to search for the space in the Confluence quick navigation via the search box). But if I select a menu, I can still see it in the drop down.
Is there a bug with this feature?
From the documentation:
If a space is archived, that space and its contents:
Won't appear in the Confluence search results unless you select Search archived spaces. This option is hidden if there are no archived spaces.
Won't appear on any dropdown menus, including the Confluence quick navigation, which drops down when you enter text in the search box.
Won't appear in the general spaces lists in the Space Directory, but will instead appear under the Archived Spaces list. It will, however, still appear under any categories it was labeled with.
Won't show up in activity streams when updated.