Delete button not working in Global Inbox

I have a few files in my Global Inbox that I no longer need.

But when I click on them to select them, the Delete button is greyed out. Out of curiosity, I imported a few test files and the Delete button doesn’t work for those, either.

I can drag them to the Trash, and the keyboard shortcut (⌘-delete) works, so it’s not like it’s impossible to delete them.

I’m just curious why the Delete button doesn’t work in the Global Inbox. (It works everywhere else.)

Are you referring to a Toolbar button or menu item?