I don't know what I did to cause this, but the icons on my desktop are unresponsive. When I click on them, nothing happens -- it's as though they weren't there at all. I can tell via Dolphin that all the information in the desktop folders is still there. I tried adding a desktop folder and that added folder was visible via Dolphin, but it didn't show up on the desktop. Even a hard reboot did not change the behavior.

So how can I resuscitate the folders and other stuff on my desktop?