My MATE desktop 1.16.2 has stopped redrawing the background. The effect being that when I move a window, the locations where the desktop background would normally be shown, now shows smeared out samples of the window I am moving.
My desktop background was originally set to show Cosmos slide show, selected from the Appearance Preferences menu.
When I mouse-click right-button on the desktop area, no menu appear. Normally it would show a menu with a Change Desktop Background
item.