focus follows mouse: fullscreen windows raising and lowering randomly

Fullscreen window is raised above another window when mouse moves over it. Non-fullscreen window is raised above fullscren window when mouse moves away from it (to a different monitor). also described here: !https://forum.xfce.org/viewtopic.php?id=13591 The same happens in kwin, metacity and maybe others. That does not make it right or desirable though. It is an annoying and useless behavior. I'd be happy to discuss a bounty.