private void kalendar_ItemDeleted(object sender, ItemEventArgs e)
        {
            MyTermin deletedTermin        = (MyTermin)e.Item;
            Subject  deletedTerminSubject = deletedTermin.ForSubject;

            TerminHandler.Instance.RemoveTermin(deletedTermin);
            SubjectHandler.Instance.ChangeUnscheduledTermins(deletedTerminSubject.Id, false);

            (Window.GetWindow(this) as MainWindow).GlobalnaShema.globalCalendar.Schedule.Items.Remove(deletedTermin);

            UpdateSubjectRow(deletedTerminSubject);

            SubjectsList.UnselectAll();
        }
        /// <summary>
        /// Mijenjamo boju i ToolTip reda u listi predmeta u skladu sa brojem NEraspoređenih termina.
        /// </summary>
        /// <param name="subject"></param>
        private void UpdateSubjectRow(Subject subject)
        {
            DataGridRow row = SubjectsList.ItemContainerGenerator.ContainerFromItem(subject) as DataGridRow;

            if (subject.UnscheduledTermins < 1)
            {
                row.Background = Brushes.PaleGreen;
                row.ToolTip    = "Predmet " + subject.Name + " je raspoređen.";
            }
            else
            {
                row.Background = Brushes.PaleGoldenrod; // black'n gold baby :P
                row.ToolTip    = "Predmet " + subject.Name + " ima neraspoređene termine.";
            }
            SubjectsList.UnselectAll();
        }