Ubuntu – Desktop does not show icons

Sounds like you have some items in an old gnome trash folder instead of the newer xdg trash folder. Do you need to recover the files and could you specify what you're looking for?

Even if you find out what's wrong, this still should be reported as a bug:

https://help.ubuntu.com/community/ReportingBugs

After wiping out the .config/xfce4 directory and starting over, I think I've figured out what's going on. It has to do with the alignment of dual monitors.

I have an external monitor on this laptop. If I extend the desktop and align the bottom of the laptop monitor (small) with the bottom of the external 27" monitor, things work great.

If instead I align them to reflect the real-world orientation where the laptop (primary) monitor is about 1/4 of the screen lower and on the left (which I'd prefer because it makes movement between monitors a lot smoother), that's when this behavior shows up. The tricky part is it doesn't show up until I log in again.

It appears that with this display orientation, something decides at login time that there are only three rows worth of icon space on the primary monitor (when there are actually still 7). Since there were icons below that, the whole desktop gets randomly rearranged. I can then move icons around as long as I only use the first three rows. If I try to use any row beyond that, the icon won't move. I can drag it there -- it just won't stick.

When I adjust the orientation of the two monitors, the number of apparent usable icon rows changes, even though there are no icons on the external monitor and the screen size of the primary monitor hasn't changed.

I only have full use of all icon rows if the two monitors are aligned at the bottom.