public GoogleEarthRibbonGroup()
        {
            InitializeComponent();

            viewModel   = new GoogleEarthRibbonGroupViewModel();
            DataContext = viewModel;
        }
        protected override void RefreshCore(WpfDesktop.Extension.GisEditorWpfMap currentMap, RefreshArgs refreshArgs)
        {
            base.RefreshCore(currentMap, refreshArgs);

            GoogleEarthRibbonGroupViewModel viewModel = googleEarthRibbonGroup.DataContext as GoogleEarthRibbonGroupViewModel;

            if (viewModel != null)
            {
                viewModel.RaisePropertyChanged();
            }
        }