Comment 7 for bug 880533

12.04; 12.10; 13.04 all also exhibit this behavior from time to time (currently experiencing the "Empty Trash" icon on the desktop, but opening shows files/folders. Worse though is a recent update (I guess) to 13.04 has rendered the use of "Trash" inoperable:
From Thunar, keyboard "DEL" or right-click "move to trash" result in "Are you sure want to permanently delete...." Cancel/Delete choices.

Seems relevant to this bug vs. starting a new one...but I'm open to challenge there.