Afaik you don't need to hide from the monitor to cause load by WindowServer while staying silent yourself. You just need to do graphics-intensive stuff. WindowS

Afaik you don't need to hide from the monitor to cause load by WindowServer while staying silent yourself. You just need to do graphics-intensive stuff. WindowServer then shows up as the manifestation of graphics being processed. In fact, Un-googled Chromium (without the autoupdater) easily causes load that's displayed as WindowServer's, for me—when I open a Youtube video on my oldish Macbook with a shitty integrated video card. However there's little chance that I would think this to be caused by something else.