Multiple LayoutControl instances with LayoutControlToolBox share single ToolBoxView instance. This makes the ToolBoxView useless because it indicates wrong structure of foreign LayoutControl. Workaround is to instantiate the ToolBoxViews manually: <telerik:RadLayoutControl.AdditionalCanvasItems> <telerik:LayoutControlToolBox LayoutControl="{Binding ElementName=layoutControl4}" > <telerik:LayoutControlToolBox.ToolBoxView> <telerik:LayoutControlToolBoxView /> </telerik:LayoutControlToolBox.ToolBoxView> </telerik:LayoutControlToolBox> </telerik:RadLayoutControl.AdditionalCanvasItems> By default they are instantiated internally.