Select cutted windows in section views



Hello friends 

I want to select only cutted window in section view.

IList<Reference> myRefs = uidoc.Selection.PickObjects(ObjectType.Element, new WindowsSelectionFilter());

How can i modify my selection filter

public bool AllowElement(Element elem)
        {
            if (elem.Category.Id.IntegerValue == (int)BuiltInCategory.OST_Windows)
            {
                    return true;
            }

            return false;
        }

        public bool AllowReference(Reference reference, XYZ position)
        {
            return true;
        }

Thanks in advance...