private static void OnExecuteDesignerAction(object sender, EventArgs e)
        {
            DesignerVerb verb = sender as DesignerVerb;

            if (verb != null)
            {
                DesignerAction designerAction = verb.Properties[DesignerUserDataKeys.DesignerAction] as DesignerAction;
                if (designerAction != null)
                {
                    ActivityDesigner designer = verb.Properties[DesignerUserDataKeys.Designer] as ActivityDesigner;
                    if (designer != null)
                    {
                        designer.OnExecuteDesignerAction(designerAction);
                    }
                }
            }
        }