public MainWindow() { InitializeComponent(); new BluEnergyXDesignerStart().ShowDialog(); errorService = new ValidationErrorService(this.messageListBox); originalTitle = this.Title; //register designers for the standard activities DesignerMetadata dm = new DesignerMetadata(); dm.Register(); //toolbox toolboxControl = CreateToolbox(); toolboxArea.Child = toolboxControl; CreateContextMenu(); InitializeDesigner(); StartNewWorkflow(); //override designer for the standard While activity AttributeTableBuilder atb = new AttributeTableBuilder(); atb.AddCustomAttributes(typeof(While), new DesignerAttribute(typeof(ActivityLibrary.Design.MyWhileDesigner))); MetadataStore.AddAttributeTable(atb.CreateTable()); }