I have been using XFCE to remote connect to my Ubuntu machines for awhile (Ubuntu 14.04 and XRDP), but every so often the desktop and icons seem to go missing and instead it shows a very low grade alternative. Not sure what causes this as it seems a bit random, but could be related to applying updates. Anyway the solution is to reinstall the desktop theme.
sudo apt-get install gnome-icon-theme-full tango-icon-theme --reinstall