return ((vWindow)a).Fg(b.isnull() ? null : b.mkString());
return ((vWindow)a.Deref()).Fg(b.isnull() ? null : b.mkString());
    public vDescriptor Call(vDescriptor a, vDescriptor b) {	if (!a.iswin()) {	    return Call(k$window.getWindow(), a);	}	return ((vWindow)a).Fg(b.isnull() ? null : b.mkString());    }