/// <summary>
 /// Hidden standard constructor
 /// </summary>
 protected AppViewModel()
 {
     _AppTheme = new ThemeViewModel();
     _demo     = new DocumentRootViewModel();
 }
 /// <summary>
 /// Hidden standard constructor
 /// </summary>
 protected AppViewModel()
 {
     _AppTheme = new ThemeViewModel();
     _demo     = new DocumentRootViewModel(GetService <IThemedHighlightingManager>());
 }