Dispatcher.BeginInvoke in Beta 2

Hi All, BeginInvoke() method  is not showing up under Dispatcher in App.xaml.cs Even after adding the ââ?¬Å?System. Threadingââ?¬Â and ââ?¬Å?System.ComponentModelââ?¬Â namespaces but it is shwoing up in Page.xaml.cs ? I need Dispatcher.BeginInvoke() to access the UI thread in App.xaml.cs any suggestion ? Thanks,Kartheek ...