Unresponsive display after a short period when x11 doesn't support DPMS

I am running xfce in a container, and the container seems to become unresponsive after sitting idle for about 5 mins. At first I thought it had to do with x11docker, which is what I use to run the container, but that was eventually ruled out after discovering the problem was with the power manager itself.

I wasn't paying attention initially, but when I run the container, I was getting the following messages:

Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".
Xlib:  extension "DPMS" missing on display ":102".

They would just fill the screen, but I paid them no heed.

After I ran the command:

xfconf-query -c xfce4-power-manager --create --property /xfce4-power-manager/presentation-mode --type 'bool' --set 'true'

The messages stopped appearing.

So it seems to me that the power manager is either unable to detect that DPMS is not available, or it is simply assuming it is available. I'm leaning towards the later because I see there is a check for DPMS support at compile time. I haven't bothered to look in the actual code if this is true.