This is not actually implemented yet, but from now on, "MouseFocus" means:
Focus follows mouse only when you are moving the mouse, any EnterNotify events
caused by non-mouse operations (window closing, keycommands, changing
desktops) will *not* shift focus
And once fully-implemented, "StrictMouseFocus" will mean:
Focus follows mouse on every EnterNotify event (except when the "ClientMenu"
closes or during alt+tab window cycling)
cdbaf5c04d