I though I had it nailed by switching Personal Preferences System to “Files”, but when I close out files the wall paper I have selected reverts to “default Ubuntu”.
Maybe this is caused by having installed Mate Desktop over top Unity.
Choosing Files on my laptop [UM installed directly] did not result in wall paper switch!
Thoughts …
Thanks Luke,
As you mentioned prior … install only the minimum desktop, I’m pretty certain that the fact Mate desktop is installed on top of Unity is breaking this. The wall paper is no big deal since this is a total throw away install I’m using to test and learn UM. If I decide to switch from Ubuntu to UM I will be able to choose Nautilus file manager as my default and not have an issue with wall paper as I mentioned about my laptop.