This combinator forces XMonad to *not* set _NET_DESKTOP_VIEWPORT.
This information is picked up by polybar's xworkspaces module and used
to re-group the workspaces by monitor. I (and others) find this super
confusing, but polybar doesn't not seem open to addressing it.
https://github.com/polybar/polybar/issues/2603
Opting in to the old behavior of not managing this property is one way
to work around it instead.