title: Binding to a selected object's observable collection list?
body: <p>I have two <code>DataGrid</code>s defined in the xaml.  The first is bound to one <code>ObservableCollection</code>.  I want to somehow bind the second <code>DataGrid</code> to an <code>ObservableCollection</code> property on the selected object in the first <code>DataGrid</code>.  Is there simple binding syntax for this, or do I have to do a whole lot of extra stuff in the code behind on some select event?</p>