Before configuring these widgets, right-click the desktop, go to "Desktop and Wallpaper", and under "Layout", select "Desktop ...
That's it. Exit the file and save over the existing one, and you've got an immutable OS in that VM. When you boot it from now ...
Immutable Linux distributions are all the rage, and with good reason. But which immutable distribution is the right one for you? Let's compare two of my favorites.