Space is still displayed after it's been pinned and all subpages have been deleted

Reproduction steps:

• Create a page Foo.Sub.WebHome and pay attention that Foo.WebHome does not exist
• Go in Administration > Look & Feel > Navigation Panel
• Pin "Foo" only
• Go to Foo.Sub.WebHome and delete the page

Expected result:

• Foo shouldn't be pinned anymore as there's no page at all in that space

Obtained result:

• Foo is still displayed in the navigation panel