Files don't disappear from desktop when dragged to trash or deleted

Drag a number of files to your trash folder.  The first few will go to the
trash and disappear from the desktop.  But after three or four, Nautilus
will stop updating the desktop-- the files will be moved to the trash, but
the icons will remain on the desktop.

You can then right-click on the file and your options will include "Delete
from trash" rather than "Move to trash"... 

When you "Delete from trash" the icon STILL stays on the desktop.  However,
it loses its icon and reverts to a "generic document" icon.  If you view
properties, you will not be able to set any of them and it will say that
"The permissions for the file could not be determined."