public MainWindow()
{
//this.SourceInitialized += new EventHandler(win_SourceInitialized);
InitializeComponent();
//viewport.TopLevel = false;
viewport.BorderStyle = BorderStyle.None;
viewportHost.Child = viewport;
FileBrowserPanel.Children.Add(fileBrowser);
fileBrowser.SetMainWindow(this);
OutlinerPanel.Children.Add(outliner);
outliner.SetMainWindow(this);
}