Clear queue doesn't

If I view the queue, there is a button labelled "clear queue" at the bottom. If I click this I get a message "Clearing queue "Regular update" is irreversible. You sure? This action cannot be undone." with another button labelled "clear queue". I push this button, and I get shown the list of queues each containing the same number of items in as before. Nothing has changed. I would have expected "clear queue" would erase the items in the queue.