private void StoreSelection()
        {
            AddInPackageViewModelBase selectedModel = AddInPackages.FirstOrDefault(m => m.IsSelected);

            if (selectedModel != null)
            {
                _lastSelectedId = selectedModel.Id;
            }
        }
        private void RestoreSelection()
        {
            AddInPackageViewModelBase modelToSelect = AddInPackages.FirstOrDefault(m => m.Id == _lastSelectedId);

            if (modelToSelect != null)
            {
                modelToSelect.IsSelected = true;
            }
            _lastSelectedId = null;
        }
 protected void ClearPackages()
 {
     AddInPackages.Clear();
 }