fairly early stages, but kwm (<a href="https:&#x2F;&#x2F;github.com&#x2F;koekeishiya&#x2F;kwm" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;koekeishiya&#x2F;kwm</a>) is an OS X tiling WM that supports focus-follows-mouse.