What is a smart tag? What are the types of DesignerActionItems? How do I add a smart tag to my control? How can I refresh the smart tag panel for my control? How can I modify smart tags on existing controls? How do I get undo to work for smart tag items? How do I show a collection editor from a smart tag link? How are items in different categories and different DesignerActionLists shown? What is a snapline? How do I add a snapline to my control? How do I modify properties only for new controls added to the designer? How can I host a designer in my app? How do I put my form in design mode?