The following classes provide general UI support:
IDocHostUIHandlerDispatch An interface to the Microsoft HTML parsing and rendering engine.
IOleObjectImpl Provides the principal methods through which a container communicates with a control. Manages the activation and deactivation of in-place controls.
IOleInPlaceObjectWindowlessImpl Manages the reactivation of in-place controls. Enables a windowless control to receive messages, as well as to participate in drag-and-drop operations.
IOleInPlaceActiveObjectImpl Assists communication between an in-place control and its container.
IViewObjectExImpl Enables a control to display itself directly and to notify the container of changes in its display. Provides support for flicker-free drawing, non-rectangular and transparent controls, and hit testing.