When I remove the last media file from a namespace, it does not delete the namespace. The empty namespace still exists and shows up in the media upload box from then on. This is inconsistent with pages; when you remove the last page from a namespace the namespace is removed as well.
1. Create a new page, click the "add media" button to bring up the image selector window
2. Upload a new image, write "someNamespace:image.png" in the "upload as" field to add the image to a namespace that doesn't exist.
3. Close the image selector dialog.
4. Open the image selector dialog again, click on the namespace containing the image.
5. Click on the trashcan icon beside the image, deleting the last thing in the namespace.
6. Close the image selector dialog and open it again.
Expected results: the image was be deleted along with the namespace; the namespace isn't there any more.
Actual results: the image was deleted, the namespace wasn't, so an empty namespace is still there.