Cycling behavior broken in 4.18?

[David Rosenstrauch]

I'm not sure exactly when this started happening, but recently the 
cycling behavior became broken in my XFCE installation.

Prior to 4.18, the behavior I would see when cycling windows (with 
compositor enabled) is that XFCE would pop up a small grid in the middle 
of my screen showing a snapshot of the contents of all of my windows, 
with the name of each one, and indicating which one I was about to 
select / bring to the front when I stopped cycling.

Now there is no grid of windows displayed, only a gray outline of the 
selected window, and it doesn't show either window contents or the name 
of the window.  Consequently I wind up having to guess which window I'm 
about to select based on the size and shape of the gray box.

Any idea what might have changed to break this behavior?  (And how to 
fix it?)

Thanks,

DR