protected override void OnNavigatedTo(NavigationEventArgs e) { rootPage = MainPage.Current; // setting up the combobox, and default operation OperationComboBox.ItemsSource = Enum.GetValues(typeof(OperationType)); OperationComboBox.SelectedIndex = (int)OperationType.Blur; operation = new OcvOp(); FileOpen.IsEnabled = true; FileSaving.IsEnabled = true; fpsTimer.Start(); }