void OnDocumentFrameNavigated(object sender, NavigationEventArgs e)
        {
            FrameworkElement newContent = (FrameworkElement)e.Content;

            if (newContent != null)
            {
                RibbonMergingHelper.SetMergeWith(newContent, RibbonControl);
                RibbonMergingHelper.SetMergeStatusBarWith(newContent, statusBar);
            }
        }
        void OnDocumentFrameNavigating(object sender, NavigatingEventArgs e)
        {
            if (e.Cancel)
            {
                return;
            }
            NavigationFrame  frame      = (NavigationFrame)sender;
            FrameworkElement oldContent = (FrameworkElement)frame.Content;

            if (oldContent != null)
            {
                RibbonMergingHelper.SetMergeWith(oldContent, null);
                RibbonMergingHelper.SetMergeStatusBarWith(oldContent, null);
            }
        }