This script was used long time ago, i don't know if still working in recent versions of MATE.
It was helpful to me. I later discovered all I needed was:
killall caja
to fix the issue I was having getting Caja to recognize a resize of the VM window in which it was running. For whatever reason, a resize smaller was no problem, but a resize larger replicated the background and did not respond to the GTK button press handler on the newly gained "real-estate."