public void RefFocus(ReferenceCanvas element)
        {
            FocusedElement = element;

            SubjectVisibility = Visibility.Collapsed;

            RefVisibility = Visibility.Visible;

            Update();
        }
        public IList <ICanvasElement> CreateReference()
        {
            var view = new SubjectReferenceView()
            {
                subject_Id = Subject.View.Id,
                target_Id  = Target.View.Id,
                type       = (ReferencesType)Type
            };

            var reference = new ReferenceCanvas(view, Subject, Target);

            return(new List <ICanvasElement>()
            {
                reference, reference.Arrow
            });
        }