private void OnActivatedExtensionChanged(ExtensionViewModel extension, ActivatedExtensionEventArgs e)
 {
     switch (e.ExtensionChange)
     {
         case ExtensionChange.Added:
             ActivatedExtensions.Add(extension);
             SelectedExtension = extension;
             break;
         case ExtensionChange.Removed:
             ActivatedExtensions.Remove(extension);
             SelectedExtension = ActivatedExtensions.FirstOrDefault();
             break;
         default:
             break;
     }
 }
        private void OnActivatedExtensionChanged(ExtensionViewModel extension, ActivatedExtensionEventArgs e)
        {
            switch (e.ExtensionChange)
            {
            case ExtensionChange.Added:
                ActivatedExtensions.Add(extension);
                SelectedExtension = extension;
                break;

            case ExtensionChange.Removed:
                ActivatedExtensions.Remove(extension);
                SelectedExtension = ActivatedExtensions.FirstOrDefault();
                break;

            default:
                break;
            }
        }