private void RoomListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     if (!_isLoading)
     {
         _isListChanging = true;
         _currentRoom    = _repo.LoadRoomGraph((int)RoomListBox.SelectedValue);
         _roomsViewSource.ObjectInstance = _currentRoom;
         _isListChanging = false;
     }
 }