private void AddWorkingItem()
        {
            var item = new WorkingItem() { Id = Guid.NewGuid(), Start = DateTime.Now, End = DateTime.Now.AddHours(2) };

            SelectedTodo.WorkingItems.Add(item);
            ManageWorkingItemsService.WorkingItems.Add(item);
        }
        private void OnTimeTracked(object sender, EventArgs.TimeTrackedEventArgs e)
        {
            if (selectedTodoProvider.SelectedTodo == null) { return; }

            // Add new working item to the manage working item service
            var newWorkingItem = new WorkingItem() { Id = Guid.NewGuid(), Start = e.StartTime, End = e.EndTime, Description = Description };
            manageWorkingItemsService.WorkingItems.Add(newWorkingItem);
            selectedTodoProvider.SelectedTodo.WorkingItems.Add(newWorkingItem);
        }
 private void RemoveWorkingItem()
 {
     SelectedTodo.WorkingItems.Remove(SelectedWorkingItem);
     ManageWorkingItemsService.WorkingItems.Remove(SelectedWorkingItem);
     SelectedWorkingItem = null;
 }
        private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == MainViewModelProperties.SelectedTodo)
            {
                SelectedWorkingItem = null;
                UpdateCommands();
            }

            if(e.PropertyName == MainViewModelProperties.SelectedWorkingItem)
            {
                UpdateCommands();
            }
        }