Created attachment 6070
$ grep DBG ~/.cache/upstart/startxfce4.log
Thaddaeus, yes it seems I get the bug no matter how many icons I have on my desktop. OK, I've followed your instructions to enable debugging, moved all my icons into a single folder on the desktop called "stuffs", logged out, logged back in, and grepped the startxfce4.log. Results are attached.
Created attachment 6070 upstart/ startxfce4. log
$ grep DBG ~/.cache/
Thaddaeus, yes it seems I get the bug no matter how many icons I have on my desktop. OK, I've followed your instructions to enable debugging, moved all my icons into a single folder on the desktop called "stuffs", logged out, logged back in, and grepped the startxfce4.log. Results are attached.