elementary_test -to bubble
click the next API button at the top until the last phase.
Under wayland this results in the window being black at the bottom with functional CSD in the wrong place
Under X11 the window is shown incorrectly for an instant and then self corrects (ie: it's harmlessly broken behaviour)
On wayland focusing a different window at this point causes an update to apparently correct state.
Looks like the window is drawn in a half re-layed out state, and under wayland we won't trigger a follow up update.