Since Ubuntu 14.04, the Directory structure has changed in Ubuntu 16.04, the desktop Icon placement is no longer
a collection of Icons kept in .config/xfce4/desktop/icons as it used to be, now Ubuntu uses a ".rc" file which contains
information about desktop layout, found in .config/xfce4/desktop/. The files used to configure desktop Icon
placement look like these - icons.screen0-1904x1014.rc - they are text files, when examined in a text editor, they
show the name of the Icon and its position, designated by column and row [x,y co-ordinates].
I my case I discovered 16 seperate ".rc" files each one having a different screen resolution in its name, so the
first task was to determine which of those 16 files was the current one in use for reference. By looking at the
date accessed column in the file manager, this became apparent. Leaving the file manager window open, I highlighted
the current file, I opened a terminal at the directory "desktop" with a right button click in the file manager.
The directory path was displayed in terminal, and with "sudo -s" authenticated access to this directory, using "ls"
the contents of "desktop" were listed in terminal, referring back to the open file manager window with the current
file name highlighted, all other desktop configuration files ".rc" were deleted using "rm" leaving the one which was
current, at this point the command line: sudo chattr -i ~/.config/xfce4/desktop/icons.screen0-1904x1014.rc can be
used to make the file writable and removable [-i] I then rolled up all windows to arrange the Icons in the order of
MY choice. I applied the [+i] variable to lock the file: sudo chattr +i ~/.config/xfce4/desktop/icons.screen0-1904x1014.rc
This appears to work, after days of battling with this annoying problem, I restarted the machine and to my delight
all desktop Icons were for once, where I wanted them to be, although, quite why I had 16 seperate configuration
files, I have no idea, I would imagine the system only needs one as a reference.
The Introduction of more Icons onto the desktop will require the file attributes to be changed again, so this
procedure needs to be carried out with each desktop change.
I Hope this will help all other users of Ubuntu 16.04 to solve the wandering Icon problem - best wishes: Peter Newton