An ActiveX designer that supports OLE drag and drop can display items (including ActiveX controls) in the host's toolbox. Users can click these items and drag them to locations on the designer.
To provide this feature, the designer must supply and register bitmaps that describe the items, implement the IDesignerToolbox interface, and use the site's SDesignerToolboxSite service. The interface and the service provide a way for the host and the designer to communicate about the items selected and displayed in the toolbox.