Make sure you check the latest source and bits of: WPF Toolkit DataGrid v1 DatePicker/Calendar v1 Visual State Manager Preview Ribbon Preview Silverlight Toolkit AutoCompleteBox NumericUpDown Viewbox Expander ImplicitStyleManager Charting TreeView DockPanel WrapPanel Label HeaderedContentControl HeaderedItemsControl Themes - Expression Dark / Light | Rainier Purple / Orange | Shiny Blue / Red