reject x11 NotifyVirtual and NotifyInferior mouse in events

reject x11 NotifyVirtual and NotifyInferior mouse in events

these are triggered "in passing" when mouse in events occur and do
not necessarily indicate that the mouse has entered this specific window

failing to reject such events can cause mouse-based focus policies to
attempt to set focus onto windows which are not visible, resulting in
an infinite loop where no window is actually focused