I would like to apply different layouts in different parts of a tree diagram.  I try to select a node and then do a radial arrange for its children, but get a KeyNotFoundException.  I think it is something to do with layouttraits, but not sure..

       void btn2_Click(object sender, RoutedEventArgs e)
       {
           // create a radial tree for children of the selected node
           DiagramItemCollection selection = diagram.Selection.Items;
           if (selection.Count != 0)
           {
               DiagramNode selectednode = (DiagramNode)selection[0];
               ArrangeRadial(diagram, selectednode);
           }
       }
...

       private void ArrangeRadial(Diagram diagram, DiagramNode rootnode)
       {
           TreeLayout layout = new TreeLayout();
           layout.Root = rootnode;
           layout.Type = TreeLayoutType.Radial;
           layout.Arrange(diagram);
       }

stack trace follows:

"   at System.ThrowHelper.ThrowKeyNotFoundException()\r\n   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)\r\n   at MindFusion.Layout.xcb359d3cc19bff83.xd378208b5267f7e2(Int32 xba08ce632055a1d9)\r\n   at MindFusion.Layout.xd4b26b0e9fcec224.x92d6db14469c8360(x11d78e5b469ed338 xda5bf54deb817e37, xcb359d3cc19bff83 x672ff13faf031f3d)\r\n   at MindFusion.Layout.xcb359d3cc19bff83.x35618da2db9d09c0(x11d78e5b469ed338 xda5bf54deb817e37)\r\n   at MindFusion.Layout.x3ea78caabca59bc5.x84e6892f0d4e87ad(x11d78e5b469ed338 xcd0140078338adc3, x9f305bec3115d3d9 x672ff13faf031f3d)\r\n   at MindFusion.Layout.xd4b26b0e9fcec224.xb7874248b0c0bc2d(x5660ea42023c83d2 xee6a854ae0b80ef2, x0cbf0b2191c9f896 x8d3f74e5f925679c, x78e3ce9dc43283f0 x22bfd1664c623dc4)\r\n   at MindFusion.Diagramming.Silverlight.Layout.TreeLayout.Arrange(Diagram diagram, DiagramItemCollection items)\r\n   at MindFusion.Diagramming.Silverlight.Layout.Layout.Arrange(Diagram diagram)\r\n   at TestingTreeLayout.Page.ArrangeRadial(Diagram diagram, DiagramNode rootnode)\r\n   at TestingTreeLayout.Page.btn2_Click(Object sender, RoutedEventArgs e)\r\n   at System.Windows.Controls.Primitives.ButtonBase.OnClick()\r\n   at System.Windows.Controls.Button.OnClick()\r\n   at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEve
ntArgs e)\r\n   at System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)\r\n   at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, String eventName)"

should work with this version:
https://mindfusion.eu/_temp/treelt_fix.zip